Latest Publications
2026
Bhatia, Manjeet
The reactive fingerprint of toxic alkylphenols: Insights from NO+ chemical ionization and spectroscopy Journal Article
In: Computational and Theoretical Chemistry, vol. 1257, pp. 115682, 2026.
@article{Bhatia2026,
title = {The reactive fingerprint of toxic alkylphenols: Insights from NO+ chemical ionization and spectroscopy},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1016/j.comptc.2026.115682},
doi = {https://doi.org/10.1016/j.comptc.2026.115682},
year = {2026},
date = {2026-01-15},
urldate = {2026-01-15},
journal = {Computational and Theoretical Chemistry},
volume = {1257},
pages = {115682},
abstract = {Alkylphenols, which consist of a phenolic ring attached to an alkyl chain, are widely used in industrial processes and consumer products, including food-contact materials such as plastic containers. Their broad application raises concerns regarding human exposure and environmental impact. In this work, density functional theory (DFT) was employed to investigate the electronic structure and chemical reactivity of alkylphenols using different DFT functionals. The key molecular descriptors, including ionization energy, electron affinity, HOMO–LUMO gap, and global reactivity parameters, were systematically evaluated. Excited-state properties and UV–Vis absorption spectra were further examined through time-dependent DFT (TD-DFT). The potential of NO as a reagent ion was also explored through charge transfer and H abstraction reactions. Benchmark DFT calculations confirm that B3LYP/6-311++G(d, p) is well-suited for ground-state studies, and further evaluations demonstrate that NO readily undergoes exothermic charge transfer with alkylphenols, proceeding at collision-controlled rates. In contrast, hydride abstraction is endothermic, and association pathways are not favorable. These findings underscore the potential of NO-based chemical ionization mass spectrometry (CIMS) techniques, such as PTR-MS and SIFT-MS, for the sensitive detection and quantification of alkylphenols. Overall, this comprehensive computational study provides valuable insights into the stability, reactivity, and photophysical behavior of alkylphenols, advancing their identification in both environmental monitoring and human health risk assessments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Alkylphenols, which consist of a phenolic ring attached to an alkyl chain, are widely used in industrial processes and consumer products, including food-contact materials such as plastic containers. Their broad application raises concerns regarding human exposure and environmental impact. In this work, density functional theory (DFT) was employed to investigate the electronic structure and chemical reactivity of alkylphenols using different DFT functionals. The key molecular descriptors, including ionization energy, electron affinity, HOMO–LUMO gap, and global reactivity parameters, were systematically evaluated. Excited-state properties and UV–Vis absorption spectra were further examined through time-dependent DFT (TD-DFT). The potential of NO as a reagent ion was also explored through charge transfer and H abstraction reactions. Benchmark DFT calculations confirm that B3LYP/6-311++G(d, p) is well-suited for ground-state studies, and further evaluations demonstrate that NO readily undergoes exothermic charge transfer with alkylphenols, proceeding at collision-controlled rates. In contrast, hydride abstraction is endothermic, and association pathways are not favorable. These findings underscore the potential of NO-based chemical ionization mass spectrometry (CIMS) techniques, such as PTR-MS and SIFT-MS, for the sensitive detection and quantification of alkylphenols. Overall, this comprehensive computational study provides valuable insights into the stability, reactivity, and photophysical behavior of alkylphenols, advancing their identification in both environmental monitoring and human health risk assessments.
2025
Bhatia, Manjeet
Exploring flavone reactivity: A quantum mechanical study and TD-DFT benchmark on UV-vis spectroscopy Journal Article
In: European Journal of Chemistry, vol. 16, iss. September 2025, no. 03, pp. 242-250, 2025.
@article{Bhatia2025,
title = {Exploring flavone reactivity: A quantum mechanical study and TD-DFT benchmark on UV-vis spectroscopy},
author = {Manjeet Bhatia},
url = {https://doi.org/10.5155/eurjchem.16.3.242-250.2666},
doi = {https://doi.org/10.5155/eurjchem.16.3.242-250.2666},
year = {2025},
date = {2025-09-30},
urldate = {2025-09-30},
journal = {European Journal of Chemistry},
volume = {16},
number = {03},
issue = {September 2025},
pages = {242-250},
abstract = {Flavones are known for their broad spectrum of pharmacological and biological activities, making them promising candidates for drug development and complementary medicine. In this study, a comprehensive analysis of the chemical reactivity, kinetic stability, and biological potential of the flavone molecule is performed using density functional theory (DFT) at the D3-B3LYP/6-311++G(d,p) level. The key molecular properties-proton affinity (PA), ionization energy (IE) and electron affinity (EA)-are calculated alongside global reactivity descriptors such as chemical potential (μ), chemical hardness (η), softness (σ), electrophilic index (ω), and electronegativity (χ). To ensure the reliability and cost-effectiveness of the chosen DFT method, a comparative analysis is performed using various functionals, including D3-B3LYP, wB97XD, M06-2X and MP2. Furthermore, time-dependent DFT (TD-DFT) calculations are performed with multiple functionals B3LYP, CAM-B3LYP, PBE0, M06-2X, LC-wHPBE and wB97XD to investigate the excited-state properties and UV-visible absorption spectra of flavone. The results indicate that CAM-B3LYP, M06-2X, and wB97XD provide the most accurate predictions for the absorption characteristics of the flavone molecule.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Flavones are known for their broad spectrum of pharmacological and biological activities, making them promising candidates for drug development and complementary medicine. In this study, a comprehensive analysis of the chemical reactivity, kinetic stability, and biological potential of the flavone molecule is performed using density functional theory (DFT) at the D3-B3LYP/6-311++G(d,p) level. The key molecular properties-proton affinity (PA), ionization energy (IE) and electron affinity (EA)-are calculated alongside global reactivity descriptors such as chemical potential (μ), chemical hardness (η), softness (σ), electrophilic index (ω), and electronegativity (χ). To ensure the reliability and cost-effectiveness of the chosen DFT method, a comparative analysis is performed using various functionals, including D3-B3LYP, wB97XD, M06-2X and MP2. Furthermore, time-dependent DFT (TD-DFT) calculations are performed with multiple functionals B3LYP, CAM-B3LYP, PBE0, M06-2X, LC-wHPBE and wB97XD to investigate the excited-state properties and UV-visible absorption spectra of flavone. The results indicate that CAM-B3LYP, M06-2X, and wB97XD provide the most accurate predictions for the absorption characteristics of the flavone molecule.
Bhatia, Manjeet
DFT Investigation of 1-Hydroxycyclohexyl Phenyl Ketone (Irgacure 184): Unraveling Molecular Structure and Chemical Reactivity Journal Article
In: Chemrxiv.org, pp. 1-15, 2025.
@article{Bhatia2025b,
title = {DFT Investigation of 1-Hydroxycyclohexyl Phenyl Ketone (Irgacure 184): Unraveling Molecular Structure and Chemical Reactivity},
author = {Manjeet Bhatia},
url = {https://doi.org/10.26434/chemrxiv-2025-0sd2r},
doi = {https://doi.org/10.26434/chemrxiv-2025-0sd2r},
year = {2025},
date = {2025-07-02},
urldate = {2025-07-02},
journal = {Chemrxiv.org},
pages = {1-15},
abstract = {In this study, quantum mechanical calculations are performed using the density functional theory (DFT) method B3 LYP functional and the set of 6-311 ++ G (d, p) basis to investigate the structural, chemical reactivity, and stability properties of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184). 1-hydroxycyclohexyl phenyl ketone is a widely used photoinitiator in UV- curable formulations, playing a crucial role in initiating polymerization reactions. Through a comprehensive computational analysis, the electronic structure and reactivity parameters, such as proton affinity, ionization potential (IP), chemical potential (µ), chemical hardness (η) and softness (σ), frontier molecular orbitals of HOMO-LUMO, electrophilic index (ω) and electronegativity (χ) of 1-hydroxycyclohexyl phenyl ketone have been elucidated in gas and aqueous medium. Molecular stability arising from delocalization or hyper- conjugation interactions and charge delocalization has been investigated using natural bond orbital (NBO) analysis. From the reported data, it is observed that the data on chemical reactivity from Koopmans’ approximation hold well with the DFT-computed data in aqueous medium calculations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this study, quantum mechanical calculations are performed using the density functional theory (DFT) method B3 LYP functional and the set of 6-311 ++ G (d, p) basis to investigate the structural, chemical reactivity, and stability properties of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184). 1-hydroxycyclohexyl phenyl ketone is a widely used photoinitiator in UV- curable formulations, playing a crucial role in initiating polymerization reactions. Through a comprehensive computational analysis, the electronic structure and reactivity parameters, such as proton affinity, ionization potential (IP), chemical potential (µ), chemical hardness (η) and softness (σ), frontier molecular orbitals of HOMO-LUMO, electrophilic index (ω) and electronegativity (χ) of 1-hydroxycyclohexyl phenyl ketone have been elucidated in gas and aqueous medium. Molecular stability arising from delocalization or hyper- conjugation interactions and charge delocalization has been investigated using natural bond orbital (NBO) analysis. From the reported data, it is observed that the data on chemical reactivity from Koopmans’ approximation hold well with the DFT-computed data in aqueous medium calculations.
Bhatia, Manjeet
Exploring alkylpyrazine stability across aggregation states: a DFT perspective Journal Article
In: Discover Chemistry, vol. 2, no. 134, 2025.
@article{nokey,
title = {Exploring alkylpyrazine stability across aggregation states: a DFT perspective},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1007/s44371-025-00207-x},
doi = {https://doi.org/10.1007/s44371-025-00207-x},
year = {2025},
date = {2025-05-31},
urldate = {2025-05-31},
journal = {Discover Chemistry},
volume = {2},
number = {134},
abstract = {Determining the structure and properties of analytes and their ions, such as proton-bound clusters, is crucial for both the theoretical understanding and practical applications of mass spectrometry, ion mobility spectrometry, and other related chemical ionization methods. Density functional theory (DFT) calculations were utilized to investigate the conformational constraints governing the formation of stable proton-bound clusters of alkylpyrazines, encompassing monomers, dimers, and trimers. Employing the B3LYP/6-31+G(d, p) method with D3(BJ) dispersion correction, molecular properties, including electric dipole moment, polarizability, and proton affinity, were presented and compared with results from higher basis sets like aug-cc-pVTZ, demonstrating the efficiency of the chosen approach. Natural bond orbital (NBO) calculations provided insights into natural charges, charge transfer, and stability of proton-bound dimer and trimer structures, revealing a decrease in stability from monomers to trimers. Notably, protonated trimers exhibited stacked structures, aligning with experimental observations. Various factors, including structure, electric dipole moment, polarizability, charge transfer, and steric hindrance influence the stability of alkylpyrazine clusters. Additionally, proton affinity calculations indicated a linear relationship between stability and proton affinity in monomers, with constant dissociation energies observed in proton-bound dimers regardless of proton affinity variations. The study contributes to the growing understanding of the relationship between ion mobility spectra in analytical measurements and gas ions under ambient temperature and pressure conditions, particularly for compounds relevant to food system analysis.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Determining the structure and properties of analytes and their ions, such as proton-bound clusters, is crucial for both the theoretical understanding and practical applications of mass spectrometry, ion mobility spectrometry, and other related chemical ionization methods. Density functional theory (DFT) calculations were utilized to investigate the conformational constraints governing the formation of stable proton-bound clusters of alkylpyrazines, encompassing monomers, dimers, and trimers. Employing the B3LYP/6-31+G(d, p) method with D3(BJ) dispersion correction, molecular properties, including electric dipole moment, polarizability, and proton affinity, were presented and compared with results from higher basis sets like aug-cc-pVTZ, demonstrating the efficiency of the chosen approach. Natural bond orbital (NBO) calculations provided insights into natural charges, charge transfer, and stability of proton-bound dimer and trimer structures, revealing a decrease in stability from monomers to trimers. Notably, protonated trimers exhibited stacked structures, aligning with experimental observations. Various factors, including structure, electric dipole moment, polarizability, charge transfer, and steric hindrance influence the stability of alkylpyrazine clusters. Additionally, proton affinity calculations indicated a linear relationship between stability and proton affinity in monomers, with constant dissociation energies observed in proton-bound dimers regardless of proton affinity variations. The study contributes to the growing understanding of the relationship between ion mobility spectra in analytical measurements and gas ions under ambient temperature and pressure conditions, particularly for compounds relevant to food system analysis.
Bhatia, Manjeet
In: Journal of Mass Spectrometry, vol. 60, iss. 2, pp. e5105, 2025.
@article{nokey,
title = {Erratum—Integrating DFT and CI‐MS Techniques to Assess Benzophenone Derivatives in Food Packaging: Implications for Enhancing Food Quality and Safety},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1002/jms.5105},
doi = {https://doi.org/10.1002/jms.5105},
year = {2025},
date = {2025-01-17},
journal = {Journal of Mass Spectrometry},
volume = {60},
issue = {2},
pages = {e5105},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bhatia, Manjeet
Basics of utilizing NH4+ ions for accurate phthalate ester quantification via selected ion flow tube mass spectrometry in food Journal Article
In: European Journal of Mass Spectrometry, vol. 31, iss. 1-2, pp. 29-37, 2025.
@article{Bhatia2025c,
title = {Basics of utilizing NH4+ ions for accurate phthalate ester quantification via selected ion flow tube mass spectrometry in food},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1177/14690667241310351},
doi = {https://doi.org/10.1177/14690667241310351},
year = {2025},
date = {2025-01-08},
journal = {European Journal of Mass Spectrometry},
volume = {31},
issue = {1-2},
pages = {29-37},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2024
Bhatia, Manjeet
In: Rapid Communications in Mass Spectrometry, vol. 38, iss. 18, pp. e9863, 2024.
@article{Bhatia2024e,
title = {Computational insights into phthalate ester-linked VOCs: A density functional theory (DFT)-based approach for chemical ionization mass spectrometry (CI-MS) analysis},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1002/rcm.9863},
doi = {https://doi.org/10.1002/rcm.9863},
year = {2024},
date = {2024-07-05},
urldate = {2024-07-05},
journal = {Rapid Communications in Mass Spectrometry},
volume = {38},
issue = {18},
pages = {e9863},
abstract = {The presence of volatile organic compounds (VOCs), notably diethyl phthalate, dimethyl phthalate, di-n-butyl phthalate, di(2-ethylhexyl) phthalate, and similar compounds in soft drinks, raises significant concerns due to their known or potential adverse health effects. Monitoring these compounds is imperative to comprehend their implications on human health and the overall quality of soft drinks. Chemical ionization mass spectrometry (CI-MS) techniques emerge as powerful tools for VOC quantification in soft drinks, offering fast analysis times, high detection sensitivity, real-time analysis capabilities, and versatility across various scientific fields. Achieving absolute quantification of VOCs using proton transfer reaction mass spectrometry (PTR-MS) presents challenges, with individual VOC calibration proving labor intensive. Theoretical approaches pioneered by Su and colleagues, including density functional theory (DFT), offer avenues for approximating VOC concentrations and understanding ion-molecule reactions. Specifically, DFT method B3LYP/6–311++G(d, p) computes molecular parameters like dipole moment, polarizability, proton affinity, and ionization energy for large phthalate esters. Rate constants of ion-molecule reactions are determined using the parametrized trajectory method under varying E/N and temperature conditions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The presence of volatile organic compounds (VOCs), notably diethyl phthalate, dimethyl phthalate, di-n-butyl phthalate, di(2-ethylhexyl) phthalate, and similar compounds in soft drinks, raises significant concerns due to their known or potential adverse health effects. Monitoring these compounds is imperative to comprehend their implications on human health and the overall quality of soft drinks. Chemical ionization mass spectrometry (CI-MS) techniques emerge as powerful tools for VOC quantification in soft drinks, offering fast analysis times, high detection sensitivity, real-time analysis capabilities, and versatility across various scientific fields. Achieving absolute quantification of VOCs using proton transfer reaction mass spectrometry (PTR-MS) presents challenges, with individual VOC calibration proving labor intensive. Theoretical approaches pioneered by Su and colleagues, including density functional theory (DFT), offer avenues for approximating VOC concentrations and understanding ion-molecule reactions. Specifically, DFT method B3LYP/6–311++G(d, p) computes molecular parameters like dipole moment, polarizability, proton affinity, and ionization energy for large phthalate esters. Rate constants of ion-molecule reactions are determined using the parametrized trajectory method under varying E/N and temperature conditions.
Bhatia, Manjeet
Unveiling the Multifaceted Nature of 4‐(4‐Methylphenyl Thio) benzophenone: Electronic Structure and Excited States in Gas Phase and Solvents Journal Article
In: ChemistrySelect, vol. 9, iss. 23, pp. e202400775, 2024.
@article{Bhatia2024,
title = {Unveiling the Multifaceted Nature of 4‐(4‐Methylphenyl Thio) benzophenone: Electronic Structure and Excited States in Gas Phase and Solvents},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1002/slct.202400775},
doi = {https://doi.org/10.1002/slct.202400775},
year = {2024},
date = {2024-06-18},
urldate = {2024-06-18},
journal = {ChemistrySelect},
volume = {9},
issue = {23},
pages = {e202400775},
abstract = {Benzophenone and its derivatives are widely used as UV filters and UV-ink photoinitiators. The photoinitiating properties of benzophenones depend on their degree of conjugation and delocalization within the molecule. By understanding how conjugation, delocalization, and different substituents affect these properties, benzophenone derivatives can be customized for specific applications. Using quantum mechanical calculations based on B3LYP/6-311++G(d, p) density functional theory (DFT), chemical reactivity, stability, and photoinitiating capabilities of 4-(4-methylphenylthio)benzophenone are analyzed. This includes studying its physical and chemical properties in the gas phase, as well as its excited state electronic transitions, vibrational characteristics, and spectroscopic properties both in gas phase and in various solvents. The DFT-computed infrared spectra match experimental results. The UV/Visible spectra shows absorption towards longer wavelengths due to extended delocalization of π-electrons. In different solvents with varying polarity, the absorption spectra exhibit high-intensity peaks, shift in excitation energy and wavelengths based on the polarity of the solvent. This knowledge allows for the development of novel initiators with customized light absorption, excited state lifetimes, and reaction selectivities, which can enhance processes like UV-curing, photopolymerization, and other light-driven reactions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Benzophenone and its derivatives are widely used as UV filters and UV-ink photoinitiators. The photoinitiating properties of benzophenones depend on their degree of conjugation and delocalization within the molecule. By understanding how conjugation, delocalization, and different substituents affect these properties, benzophenone derivatives can be customized for specific applications. Using quantum mechanical calculations based on B3LYP/6-311++G(d, p) density functional theory (DFT), chemical reactivity, stability, and photoinitiating capabilities of 4-(4-methylphenylthio)benzophenone are analyzed. This includes studying its physical and chemical properties in the gas phase, as well as its excited state electronic transitions, vibrational characteristics, and spectroscopic properties both in gas phase and in various solvents. The DFT-computed infrared spectra match experimental results. The UV/Visible spectra shows absorption towards longer wavelengths due to extended delocalization of π-electrons. In different solvents with varying polarity, the absorption spectra exhibit high-intensity peaks, shift in excitation energy and wavelengths based on the polarity of the solvent. This knowledge allows for the development of novel initiators with customized light absorption, excited state lifetimes, and reaction selectivities, which can enhance processes like UV-curing, photopolymerization, and other light-driven reactions.
Bhatia, Manjeet
In: Journal of Mass Spectrometry, vol. 59, iss. 3, pp. e5011, 2024.
@article{Bhatia2024b,
title = {Integrating density functional theory and chemical ionization mass spectrometry techniques to assess benzophenone derivatives in food packaging: implications for enhancing food quality and safety},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1002/jms.5011},
doi = {https://doi.org/10.1002/jms.5011},
year = {2024},
date = {2024-03-06},
urldate = {2024-03-06},
journal = {Journal of Mass Spectrometry},
volume = {59},
issue = {3},
pages = {e5011},
abstract = {Benzophenone and related derivatives are widely used as photoinitiators for food packaging to cure inks or lacquers with ultraviolet (UV) light on cardboard and paper. However, there are concerns about the potential health risks of their migration into food. Knowing the physical and chemical properties of benzophenone and its derivatives could play a significant role in their quantification and analysis using chemical ionization mass spectrometry (CI-MS) methods. These parameters are evaluated using B3LYP/6-311++** density functional theory (DFT) implemented on Gaussian code. Ion–molecule chemistry through the selection of reagent ions, reaction energetics and kinetics, thermodynamic stability, and reactivity of molecules deemed to foster VOC identification and quantification via CI-MS techniques. The VOCs under study are expected to undergo exothermic reactions from H3O+, NH4+, NO+, and O2+ ions, except endothermic proton transfer from NH4+ to 2-hydroxy-4-methoxybenzophenone and 2,3,4-trihydroxy benzophenone. These compounds possess less proton affinities than NH3 and are least stable in their protonated forms. The DFT computed properties provide the basis for developing reliable and accurate methods to detect and measure the presence of benzophenone and its derivatives in packaging materials and food products.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Benzophenone and related derivatives are widely used as photoinitiators for food packaging to cure inks or lacquers with ultraviolet (UV) light on cardboard and paper. However, there are concerns about the potential health risks of their migration into food. Knowing the physical and chemical properties of benzophenone and its derivatives could play a significant role in their quantification and analysis using chemical ionization mass spectrometry (CI-MS) methods. These parameters are evaluated using B3LYP/6-311++** density functional theory (DFT) implemented on Gaussian code. Ion–molecule chemistry through the selection of reagent ions, reaction energetics and kinetics, thermodynamic stability, and reactivity of molecules deemed to foster VOC identification and quantification via CI-MS techniques. The VOCs under study are expected to undergo exothermic reactions from H3O+, NH4+, NO+, and O2+ ions, except endothermic proton transfer from NH4+ to 2-hydroxy-4-methoxybenzophenone and 2,3,4-trihydroxy benzophenone. These compounds possess less proton affinities than NH3 and are least stable in their protonated forms. The DFT computed properties provide the basis for developing reliable and accurate methods to detect and measure the presence of benzophenone and its derivatives in packaging materials and food products.
Bhatia, Manjeet
An overview of conceptual-DFT based insights into global chemical reactivity of volatile sulfur compounds (VSCs) Journal Article
In: Computational Toxicology, vol. 29, pp. 100295, 2024.
@article{Bhatia2024c,
title = {An overview of conceptual-DFT based insights into global chemical reactivity of volatile sulfur compounds (VSCs)},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1016/j.comtox.2023.100295},
doi = {https://doi.org/10.1016/j.comtox.2023.100295},
year = {2024},
date = {2024-03-01},
urldate = {2024-03-01},
journal = {Computational Toxicology},
volume = {29},
pages = {100295},
abstract = {Volatile sulfur compounds (VSCs) are highly volatile and most frequently associated with oral malodor. The odor quality is associated with the size and shape of the molecule along with stability, hydrogen bonding, extended d-shell electronic behavior, and complicity of d-shell bonding. Chemical reactivity descriptors of VSCs, such as chemical hardness (η), softness (σ), chemical potential (μ), electrophilic index (ω), and electronegativity (χ) are computed at B3LYP/Aug-cc-PVTZ level of theory from the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the light of Koopmans’ approximation. Furthermore, the global reactivity parameters are evaluated from the vertical ionization potential (IP) and electron affinity (EA) to support the results of Koopmans’ theorem. These reactivity parameters offer a quantitative measure of the electronic structure and chemical properties of VSCs, offering insights into their stability, reactivity, and interaction with other molecules. A Python-based application is provided for the rapid calculation of these parameters (GitHub: Link).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Volatile sulfur compounds (VSCs) are highly volatile and most frequently associated with oral malodor. The odor quality is associated with the size and shape of the molecule along with stability, hydrogen bonding, extended d-shell electronic behavior, and complicity of d-shell bonding. Chemical reactivity descriptors of VSCs, such as chemical hardness (η), softness (σ), chemical potential (μ), electrophilic index (ω), and electronegativity (χ) are computed at B3LYP/Aug-cc-PVTZ level of theory from the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the light of Koopmans’ approximation. Furthermore, the global reactivity parameters are evaluated from the vertical ionization potential (IP) and electron affinity (EA) to support the results of Koopmans’ theorem. These reactivity parameters offer a quantitative measure of the electronic structure and chemical properties of VSCs, offering insights into their stability, reactivity, and interaction with other molecules. A Python-based application is provided for the rapid calculation of these parameters (GitHub: Link).
Bhatia, Manjeet
Charting the Reactivity Terrain of Benzophenones: A DFT-driven Exploration in Gas and Aqueous Environments Journal Article
In: Indian Journal of Advances in Chemical Science, vol. 12, iss. 1, pp. 40-47, 2024.
@article{Bhatia2024d,
title = {Charting the Reactivity Terrain of Benzophenones: A DFT-driven Exploration in Gas and Aqueous Environments},
author = {Manjeet Bhatia},
url = {10.22607/IJACS.2024.1201006},
doi = {10.22607/IJACS.2024.1201006},
year = {2024},
date = {2024-02-05},
urldate = {2024-02-05},
journal = {Indian Journal of Advances in Chemical Science},
volume = {12},
issue = {1},
pages = {40-47},
abstract = {Benzophenone and related derivatives are widely used bimolecular photoinitiators in the printing industry due to their low cost and high reactivity. Benzophenones are competent in initiating a chemical reaction to ultraviolet (UV) or visible light, which makes them valuable in UV curing applications. Chemical reactivity parameters of benzophenones are evaluated in the gas and aqueous phase using density functional theory (DFT) at B3LYP/6-311++G(d, p) combination. Global reactivity descriptors such as chemical potential (μ), chemical hardness (η), softness (σ), electrophilicity (ω), and electronegativity (χ) provide a predictive framework for a molecule’s reactivity without the need for experimental data. It is observed that substituted benzophenones are more reactive than benzophenone and chemical reactivity is improved in aqueous medium. Analogous to DFT, the approximations
of Koopmans theorem can be used as a valid method for the prediction of reactivity of molecules in gas and aqueous phase. These descriptors help in understanding and rationalizing the mechanisms of chemical reactions, especially in terms of electron transfer processes. A link to the python+Tkinter code for the calculation of global reactivity parameters is Link (https://github.com/ Manjeetkb/Reactivity_parameters.git).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Benzophenone and related derivatives are widely used bimolecular photoinitiators in the printing industry due to their low cost and high reactivity. Benzophenones are competent in initiating a chemical reaction to ultraviolet (UV) or visible light, which makes them valuable in UV curing applications. Chemical reactivity parameters of benzophenones are evaluated in the gas and aqueous phase using density functional theory (DFT) at B3LYP/6-311++G(d, p) combination. Global reactivity descriptors such as chemical potential (μ), chemical hardness (η), softness (σ), electrophilicity (ω), and electronegativity (χ) provide a predictive framework for a molecule’s reactivity without the need for experimental data. It is observed that substituted benzophenones are more reactive than benzophenone and chemical reactivity is improved in aqueous medium. Analogous to DFT, the approximations
of Koopmans theorem can be used as a valid method for the prediction of reactivity of molecules in gas and aqueous phase. These descriptors help in understanding and rationalizing the mechanisms of chemical reactions, especially in terms of electron transfer processes. A link to the python+Tkinter code for the calculation of global reactivity parameters is Link (https://github.com/ Manjeetkb/Reactivity_parameters.git).
of Koopmans theorem can be used as a valid method for the prediction of reactivity of molecules in gas and aqueous phase. These descriptors help in understanding and rationalizing the mechanisms of chemical reactions, especially in terms of electron transfer processes. A link to the python+Tkinter code for the calculation of global reactivity parameters is Link (https://github.com/ Manjeetkb/Reactivity_parameters.git).
2023
Bhatia, Manjeet
A Gaussian process regression (GPR) quest to predict HOMO-LUMO energy Journal Article
In: Chemrxiv.org, 2023.
@article{Bhatia2023c,
title = {A Gaussian process regression (GPR) quest to predict HOMO-LUMO energy},
author = {Manjeet Bhatia},
url = {https://doi.org/10.26434/chemrxiv-2023-v},
doi = {https://doi.org/10.26434/chemrxiv-2023-v},
year = {2023},
date = {2023-07-20},
urldate = {2023-07-20},
journal = {Chemrxiv.org},
abstract = {Machine learning methods employ statistical algorithms and pattern recognition techniques to learn patterns and make predictions based on statistical patterns. Global reactivity descriptors, such as HOMO-LUMO energy, chemical potential (µ), chemical hardness (η), softness (σ) and electrophilic index (ω) are predicted using Gaussian process regression (GPR) machine learning method. GPR predicted values are in close agreement with the values obtained via ab initio methods. Over 85% prediction accuracy in HOMO energies and reactivity parameters is observed, while LUMO energies were in good range with the DFT evaluations. An appropriate kernel combination with proper tuning of parameters and the selection of quality correlated data can make the GPR model robust and powerful. Machine learning models like GPR could play a pivotal role in assisting and accelerating ab initio calculations and providing insights for highly complex molecular systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Machine learning methods employ statistical algorithms and pattern recognition techniques to learn patterns and make predictions based on statistical patterns. Global reactivity descriptors, such as HOMO-LUMO energy, chemical potential (µ), chemical hardness (η), softness (σ) and electrophilic index (ω) are predicted using Gaussian process regression (GPR) machine learning method. GPR predicted values are in close agreement with the values obtained via ab initio methods. Over 85% prediction accuracy in HOMO energies and reactivity parameters is observed, while LUMO energies were in good range with the DFT evaluations. An appropriate kernel combination with proper tuning of parameters and the selection of quality correlated data can make the GPR model robust and powerful. Machine learning models like GPR could play a pivotal role in assisting and accelerating ab initio calculations and providing insights for highly complex molecular systems.
Bhatia, Manjeet
A review of parametrized trajectory method-based chemical kinetics application to food and flavor analysis Journal Article
In: European Food Research and Technology, vol. 249, pp. 1953–1968, 2023.
@article{Bhatia2023b,
title = {A review of parametrized trajectory method-based chemical kinetics application to food and flavor analysis},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1007/s00217-023-04289-8},
doi = {https://doi.org/10.1007/s00217-023-04289-8},
year = {2023},
date = {2023-05-17},
urldate = {2023-05-17},
journal = {European Food Research and Technology},
volume = {249},
pages = {1953–1968},
abstract = {Volatile organic compounds (VOCs) are considered crucial in determining the aroma and flavor profile of food and fermented beverages. Volatile compounds emitted from food carry invaluable information that can be used to detect subtle changes in food products and are viewed as an indicator of food quality. Chemical ionization-based direct-ionization mass spectrometry (DI-MS) techniques, which are prominently used in determining the concentration of an unknown mixture of compounds, for example, air, are reviewed. DI-MS techniques, such as proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow tube mass spectrometry (SIFT-MS) offer real-time, rapid, high-sensitivity, and online analysis of VOCs. Accurate quantification of trace gases can be achieved without instrument calibration if we know the rate coefficients of ion-molecule reactions. The rate coefficients can be used to calculate the sensitivities of VOCs as detected by chemical ionization mass spectrometry (CI-MS) methods. The neutral molecule’s electric dipole moment and polarizability are essential input parameters to compute rates using parametrized trajectory model. An application for the calculation of rates is provided (GitHub: link) under elevated energy and temperature conditions, along with a database dedicated to physical and chemical properties of most exotic VOCs linked to food and alcoholic beverages.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Volatile organic compounds (VOCs) are considered crucial in determining the aroma and flavor profile of food and fermented beverages. Volatile compounds emitted from food carry invaluable information that can be used to detect subtle changes in food products and are viewed as an indicator of food quality. Chemical ionization-based direct-ionization mass spectrometry (DI-MS) techniques, which are prominently used in determining the concentration of an unknown mixture of compounds, for example, air, are reviewed. DI-MS techniques, such as proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow tube mass spectrometry (SIFT-MS) offer real-time, rapid, high-sensitivity, and online analysis of VOCs. Accurate quantification of trace gases can be achieved without instrument calibration if we know the rate coefficients of ion-molecule reactions. The rate coefficients can be used to calculate the sensitivities of VOCs as detected by chemical ionization mass spectrometry (CI-MS) methods. The neutral molecule’s electric dipole moment and polarizability are essential input parameters to compute rates using parametrized trajectory model. An application for the calculation of rates is provided (GitHub: link) under elevated energy and temperature conditions, along with a database dedicated to physical and chemical properties of most exotic VOCs linked to food and alcoholic beverages.
Bhatia, Manjeet
A DFT evaluation of molecular reactivity of volatile organic compounds in support of chemical ionization mass spectrometry Journal Article
In: Computational and Theoretical Chemistry, vol. 1223, pp. 114101, 2023.
@article{Bhatia2023,
title = {A DFT evaluation of molecular reactivity of volatile organic compounds in support of chemical ionization mass spectrometry},
author = {Manjeet Bhatia},
url = {https://doi.org/10.1016/j.comptc.2023.114101},
doi = {https://doi.org/10.1016/j.comptc.2023.114101},
year = {2023},
date = {2023-03-15},
urldate = {2023-03-15},
journal = {Computational and Theoretical Chemistry},
volume = {1223},
pages = {114101},
abstract = {Gas-phase molecular properties of volatile organic compounds (VOCs) play an important role in the selection of gas-phase reagent ions for chemical ionization mass spectrometry (CI-MS). Chemical ionization-based mass spectrometry techniques such as proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow-tube mass spectrometry (SIFT-MS) provide real-time, rapid, and online detection and quantification of VOCs using thermodynamics and kinetics of ion-molecule gas-phase reactions. We apply hybrid density functional theory (DFT) to compute proton affinity (PA), ionization energy (IE), and global reactivity parameters for VOCs, which are widely regarded as the primary sources of taints and off-flavors in wine. Atomic polar tensor (APT) charges and total energies at the stationary point for neutral and protonated molecules are also computed. PA and IE values determine the CI-MS mode of reactions, either proton transfer or electron transfer from the reagent gas ions to VOCs. Global reactivity parameters, such as chemical potential (), chemical hardness (), softness (), and electrophilic nature () as obtained from frontier molecular orbitals, are considered useful in rationalizing the chemical reactivity patterns of the molecules. A benchmark calculation of indole molecule with MP2, B3LYP, and M06-2X DFT methods at thermodynamically and kinetically stable protonation sites further supports the applied DFT method. Since limited data are available on computed parameters, the reported values would support CI-MS quantification of trace-level VOCs not only in wine but also in various food products.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gas-phase molecular properties of volatile organic compounds (VOCs) play an important role in the selection of gas-phase reagent ions for chemical ionization mass spectrometry (CI-MS). Chemical ionization-based mass spectrometry techniques such as proton transfer reaction mass spectrometry (PTR-MS) and selected ion flow-tube mass spectrometry (SIFT-MS) provide real-time, rapid, and online detection and quantification of VOCs using thermodynamics and kinetics of ion-molecule gas-phase reactions. We apply hybrid density functional theory (DFT) to compute proton affinity (PA), ionization energy (IE), and global reactivity parameters for VOCs, which are widely regarded as the primary sources of taints and off-flavors in wine. Atomic polar tensor (APT) charges and total energies at the stationary point for neutral and protonated molecules are also computed. PA and IE values determine the CI-MS mode of reactions, either proton transfer or electron transfer from the reagent gas ions to VOCs. Global reactivity parameters, such as chemical potential (), chemical hardness (), softness (), and electrophilic nature () as obtained from frontier molecular orbitals, are considered useful in rationalizing the chemical reactivity patterns of the molecules. A benchmark calculation of indole molecule with MP2, B3LYP, and M06-2X DFT methods at thermodynamically and kinetically stable protonation sites further supports the applied DFT method. Since limited data are available on computed parameters, the reported values would support CI-MS quantification of trace-level VOCs not only in wine but also in various food products.
2022
Bhatia, Manjeet
Gaussian Process Regression (GPR) Method for the Prediction of Rate Coefficients of Gas-phase Reactions in Chemical Ionization Mass Spectrometry Journal Article
In: Chemrxiv.org, pp. 1-16, 2022.
@article{Bhatia2022c,
title = {Gaussian Process Regression (GPR) Method for the Prediction of Rate Coefficients of Gas-phase Reactions in Chemical Ionization Mass Spectrometry},
author = {Manjeet Bhatia},
url = {https://doi.org/10.26434/chemrxiv-2022-x},
doi = {https://doi.org/10.26434/chemrxiv-2022-x},
year = {2022},
date = {2022-12-15},
journal = {Chemrxiv.org},
pages = {1-16},
abstract = {Reaction kinetics of chemical ionization mass spectrometry (CI-MS) based ion-molecule reactions is an important component in the quantification of trace-level volatile organic compounds (VOCs). The rate coefficients of such CI-MS reactions are predicted using the Gaussian process regression (GPR) machine learning method from the dipole moment, polarizability, and molecular weight of the molecules, mitigating experimental complexity in CI-MS rate coefficient estimation. GPR can make predictions combining prior knowledge (kernel function) which is considered the heart of the GPR model and provide uncertainty measures over predictions. A suitable kernel combination with proper tuning of parameters can make the Gaussian process more robust and powerful. Various kernel combinations, such as kernel addition and multiplication, are tested in the GPR prediction of rates. A blend of radial basis function (RBF), white noise, and squared exponential kernel performs better, and the predicted rates are in close agreement with the experimental rates. GPR provides an alternative to the capture collision rates and can be useful when there are no experimental data available and/or the available data contain large uncertainty in the rate coefficients.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Reaction kinetics of chemical ionization mass spectrometry (CI-MS) based ion-molecule reactions is an important component in the quantification of trace-level volatile organic compounds (VOCs). The rate coefficients of such CI-MS reactions are predicted using the Gaussian process regression (GPR) machine learning method from the dipole moment, polarizability, and molecular weight of the molecules, mitigating experimental complexity in CI-MS rate coefficient estimation. GPR can make predictions combining prior knowledge (kernel function) which is considered the heart of the GPR model and provide uncertainty measures over predictions. A suitable kernel combination with proper tuning of parameters can make the Gaussian process more robust and powerful. Various kernel combinations, such as kernel addition and multiplication, are tested in the GPR prediction of rates. A blend of radial basis function (RBF), white noise, and squared exponential kernel performs better, and the predicted rates are in close agreement with the experimental rates. GPR provides an alternative to the capture collision rates and can be useful when there are no experimental data available and/or the available data contain large uncertainty in the rate coefficients.
Bhatia, Manjeet; Manini, Nicola; Biasioli, Franco; Cappellin, Luca
Calculated rate coefficients between CI-MS reagent ions and organosulfur compounds causing food taints and off-flavours Journal Article
In: International Journal of Mass Spectrometry, vol. 478, pp. 116860, 2022.
@article{Bhatia2022,
title = {Calculated rate coefficients between CI-MS reagent ions and organosulfur compounds causing food taints and off-flavours},
author = {Manjeet Bhatia and Nicola Manini and Franco Biasioli and Luca Cappellin},
url = {https://doi.org/10.1016/j.ijms.2022.116860},
doi = {https://doi.org/10.1016/j.ijms.2022.116860},
year = {2022},
date = {2022-05-13},
urldate = {2022-05-13},
journal = {International Journal of Mass Spectrometry},
volume = {478},
pages = {116860},
abstract = {Volatile sulfur compounds play a crucial role in the aroma profile of food and fermented beverages. We explore chemical-ionization mass spectrometry (CI-MS) ion-molecule reaction kinetics of commonly used reagent ions to a list of volatile organic sulfur compounds (VOSCs). We compute the rate coefficients of ion-molecule reactions, useful for the accurate identification and quantification of trace gases, using capture collision models based on the electric dipole moment and polarizability of the neutral VOSCs. To this aim, we evaluate molecular properties, such as the electric dipole moment, polarizability, proton affinity (PA), and ionization energy (IE) for each VOSC, by means of hybrid density functional theory (DFT) simulations. The PA and IE values are useful in the selection of appropriate reagent ions to be used in CI-MS. We thoroughly investigate collision rate coefficients at effective temperatures and internal energies, as relevant for highly energetic proton transfer reaction mass spectrometry (PTR-MS) drift tube conditions. The data provided will be valuable for the rapid quantification of VOSCs in food and fermented beverages.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Volatile sulfur compounds play a crucial role in the aroma profile of food and fermented beverages. We explore chemical-ionization mass spectrometry (CI-MS) ion-molecule reaction kinetics of commonly used reagent ions to a list of volatile organic sulfur compounds (VOSCs). We compute the rate coefficients of ion-molecule reactions, useful for the accurate identification and quantification of trace gases, using capture collision models based on the electric dipole moment and polarizability of the neutral VOSCs. To this aim, we evaluate molecular properties, such as the electric dipole moment, polarizability, proton affinity (PA), and ionization energy (IE) for each VOSC, by means of hybrid density functional theory (DFT) simulations. The PA and IE values are useful in the selection of appropriate reagent ions to be used in CI-MS. We thoroughly investigate collision rate coefficients at effective temperatures and internal energies, as relevant for highly energetic proton transfer reaction mass spectrometry (PTR-MS) drift tube conditions. The data provided will be valuable for the rapid quantification of VOSCs in food and fermented beverages.
Bhatia, Manjeet; Manini, Nicola; Biasioli, Franco; Cappellin, Luca
Theoretical Investigation of Charge Transfer from NO+ and O2+ Ions to Wine-Related Volatile Compounds for Mass Spectrometry Journal Article
In: Journal of the American Society for Mass Spectrometry, vol. 33, iss. 2, pp. 251-264, 2022.
@article{Bhatia2022b,
title = {Theoretical Investigation of Charge Transfer from NO+ and O2+ Ions to Wine-Related Volatile Compounds for Mass Spectrometry},
author = {Manjeet Bhatia and Nicola Manini and Franco Biasioli and Luca Cappellin},
url = {https://doi.org/10.1021/jasms.1c00253},
doi = {https://doi.org/10.1021/jasms.1c00253},
year = {2022},
date = {2022-01-12},
urldate = {2022-01-12},
journal = {Journal of the American Society for Mass Spectrometry},
volume = {33},
issue = {2},
pages = {251-264},
abstract = {Density-functional theory (DFT) is used to obtain the molecular data essential for predicting the reaction kinetics of chemical-ionization-mass spectrometry (CI-MS), as applied in the analysis of volatile organic compounds (VOCs). We study charge-transfer reactions from NO+ and O2+ reagent ions to VOCs related to cork-taint and off-flavor in wine. We evaluate the collision rate coefficients of ion–molecule reactions by means of collision-based models. Many NO+ and O2+ reactions are known to proceed at or close to their respective collision rates. Factors affecting the collision reaction rates, including electric-dipole moment and polarizability, temperature, and electric field are addressed, targeting the conditions of standard CI-MS techniques. The molecular electric-dipole moment and polarizability are the basic ingredients for the calculation of collision reaction rates in ion–molecule collision-based models. Using quantum-mechanical calculations, we evaluate these quantities for the neutral VOCs. We also investigate the thermodynamic feasibility of the reactions by computing the enthalpy change in these charge-transfer reactions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Density-functional theory (DFT) is used to obtain the molecular data essential for predicting the reaction kinetics of chemical-ionization-mass spectrometry (CI-MS), as applied in the analysis of volatile organic compounds (VOCs). We study charge-transfer reactions from NO+ and O2+ reagent ions to VOCs related to cork-taint and off-flavor in wine. We evaluate the collision rate coefficients of ion–molecule reactions by means of collision-based models. Many NO+ and O2+ reactions are known to proceed at or close to their respective collision rates. Factors affecting the collision reaction rates, including electric-dipole moment and polarizability, temperature, and electric field are addressed, targeting the conditions of standard CI-MS techniques. The molecular electric-dipole moment and polarizability are the basic ingredients for the calculation of collision reaction rates in ion–molecule collision-based models. Using quantum-mechanical calculations, we evaluate these quantities for the neutral VOCs. We also investigate the thermodynamic feasibility of the reactions by computing the enthalpy change in these charge-transfer reactions.
2020
Bhatia, Manjeet; Biasioli, Franco; Cappellin, Luca; Piseri, Paolo; Manini, Nicola
Ab initio calculation of the proton transfer reaction rate coefficients to volatile organic compounds related to cork taint in wine Bachelor Thesis
2020.
@bachelorthesis{Bhatia2020,
title = {Ab initio calculation of the proton transfer reaction rate coefficients to volatile organic compounds related to cork taint in wine},
author = {Manjeet Bhatia and Franco Biasioli and Luca Cappellin and Paolo Piseri and Nicola Manini},
url = {https://doi.org/10.1002/jms.4592},
doi = {https://doi.org/10.1002/jms.4592},
year = {2020},
date = {2020-06-15},
urldate = {2020-06-15},
journal = {Journal of Mass Spectrometry},
volume = {55},
issue = {11},
pages = {e4592},
abstract = {We compute the proton transfer rates to a range of volatile organic compounds (VOCs) related to cork taint in wine. These rates are useful to support quantification in proton-transfer-reaction mass spectrometry (PTR-MS) and in selected-ion flow-tube mass spectrometry (SIFT-MS). We apply the average dipole orientation theory and the parameterized trajectory method to evaluate the rate coefficients for proton transfer occurring in ion–molecule collision, from both H3O+ and NH urn:x-wiley:jms:media:jms4592:jms4592-math-0001 to the VOCs. The main input ingredients for these methods are the electric dipole moment and polarizability of the VOC molecules, which we evaluate by means of quantum chemical calculations based on density functional theory. We provide new data for proton transfer rate coefficients of compounds responsible for cork taint and off-flavor in wine such as chloroanisoles, bromoanisoles, methylisoborneol, guaiacol, and terpenes.},
keywords = {},
pubstate = {published},
tppubtype = {bachelorthesis}
}
We compute the proton transfer rates to a range of volatile organic compounds (VOCs) related to cork taint in wine. These rates are useful to support quantification in proton-transfer-reaction mass spectrometry (PTR-MS) and in selected-ion flow-tube mass spectrometry (SIFT-MS). We apply the average dipole orientation theory and the parameterized trajectory method to evaluate the rate coefficients for proton transfer occurring in ion–molecule collision, from both H3O+ and NH urn:x-wiley:jms:media:jms4592:jms4592-math-0001 to the VOCs. The main input ingredients for these methods are the electric dipole moment and polarizability of the VOC molecules, which we evaluate by means of quantum chemical calculations based on density functional theory. We provide new data for proton transfer rate coefficients of compounds responsible for cork taint and off-flavor in wine such as chloroanisoles, bromoanisoles, methylisoborneol, guaiacol, and terpenes.
2019
Bhatia, Manjeet; Sharma, Uma Shankar; Srivastava, Anurag
Chromium Influenced High Magnetic Moment and Half-Metallic Nature of GaN Nanotube Journal Article
In: Journal of Nanoscience and Nanotechnology, vol. 19, no. 7, pp. 4214-4219(6), 2019.
@article{Bhatia2019,
title = {Chromium Influenced High Magnetic Moment and Half-Metallic Nature of GaN Nanotube},
author = {Manjeet Bhatia and Uma Shankar Sharma and Anurag Srivastava},
url = {https://doi.org/10.1166/jnn.2019.16286},
doi = {https://doi.org/10.1166/jnn.2019.16286},
year = {2019},
date = {2019-07-01},
urldate = {2019-07-01},
journal = { Journal of Nanoscience and Nanotechnology},
volume = {19},
number = {7},
pages = {4214-4219(6)},
abstract = {Density functional theory-based calculations have been performed to analyze the electronic and magnetic properties of chromium doped (6, 0) GaN nanotube. The structural stability of GaN nano-tube has been defined in terms of formation energy, which increases as a function of magnetic impurity (Cr). The study demonstrates that the direct band gap semiconducting GaN nanotube transforms to half-metallic as a function of Cr introduction to GaN. This half metallic nature with high magnetic moment of Cr doped GaN nanotube can be a key parameter for its use in spintronics applications. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Density functional theory-based calculations have been performed to analyze the electronic and magnetic properties of chromium doped (6, 0) GaN nanotube. The structural stability of GaN nano-tube has been defined in terms of formation energy, which increases as a function of magnetic impurity (Cr). The study demonstrates that the direct band gap semiconducting GaN nanotube transforms to half-metallic as a function of Cr introduction to GaN. This half metallic nature with high magnetic moment of Cr doped GaN nanotube can be a key parameter for its use in spintronics applications.
Khomenko, Iuliia; Brambilla, Fabio; Bhatia, Manjeet; Biasioli, Franco
PTR-ToF-MS VOC profiling of raw and cooked gilthead sea bream (Sparus aurata) from different geographical origin Proceedings Article
In: 8th International PTR-MS Conference 2019, Innsbruck-Austria, 4th February-8th February 2019, pp. 220-221, Innsbruck – Austria, 2019.
@inproceedings{Khomenko2019,
title = {PTR-ToF-MS VOC profiling of raw and cooked gilthead sea bream (Sparus aurata) from different geographical origin},
author = {Iuliia Khomenko and Fabio Brambilla and Manjeet Bhatia and Franco Biasioli},
url = {https://openpub.fmach.it/handle/10449/69312},
doi = {https://hdl.handle.net/10449/69312},
year = {2019},
date = {2019-01-01},
urldate = {2019-01-01},
booktitle = {8th International PTR-MS Conference 2019, Innsbruck-Austria, 4th February-8th February 2019},
pages = {220-221},
address = {Innsbruck - Austria},
abstract = {Fish volatile compounds provide information both on quality and freshness of fish. In this study, proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) equipped with a multipurpose head-space automated sampler was successfully used to investigate the VOC profiles of raw and cooked gilthead sea bream (Sparus aurata) from different geographical origins and farming methods },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Fish volatile compounds provide information both on quality and freshness of fish. In this study, proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) equipped with a multipurpose head-space automated sampler was successfully used to investigate the VOC profiles of raw and cooked gilthead sea bream (Sparus aurata) from different geographical origins and farming methods
2018
Khan, Md Shahzad; Bhatia, Manjeet; Srivastava, Anurag
Structural and electronic properties of rectangular CdTe nanowire: A DST study Journal Article
In: AIP Conference Proceedings, vol. 1953, iss. 1, pp. 140136, 2018.
@article{Khan2018,
title = {Structural and electronic properties of rectangular CdTe nanowire: A DST study},
author = {Md Shahzad Khan and Manjeet Bhatia and Anurag Srivastava},
url = {https://doi.org/10.1063/1.5033311},
doi = {https://doi.org/10.1063/1.5033311},
year = {2018},
date = {2018-05-08},
urldate = {2018-05-08},
journal = {AIP Conference Proceedings},
volume = {1953},
issue = {1},
pages = {140136},
abstract = {CdTe rectangular nanowire of different diameter in zinc-blende phase is investigated using density functional theory. Enhancement of diameter increased stability and improved electronic qualities suitable for device purpose applications. Cohesive energy per atom enhanced on enlarging diameter advocating the stability. Large diameter nanowire (22.62Å) exhibits bandgap of 1.21eV and electronic effective mass is observed to be 0.51me. The bonding between Cd-Te atoms are predominantly observed as covalent assuring its inertness towards moisture.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
CdTe rectangular nanowire of different diameter in zinc-blende phase is investigated using density functional theory. Enhancement of diameter increased stability and improved electronic qualities suitable for device purpose applications. Cohesive energy per atom enhanced on enlarging diameter advocating the stability. Large diameter nanowire (22.62Å) exhibits bandgap of 1.21eV and electronic effective mass is observed to be 0.51me. The bonding between Cd-Te atoms are predominantly observed as covalent assuring its inertness towards moisture.
Bhatia, Manjeet; Khan, Md Shahzad; Srivastava, Anurag
Pressure induced phase transition in CdTe nanowire: A DFT study Journal Article
In: AIP Conference Proceedings, vol. 1953, iss. 1, pp. 040033, 2018.
@article{nokey,
title = {Pressure induced phase transition in CdTe nanowire: A DFT study},
author = {Manjeet Bhatia and Md Shahzad Khan and Anurag Srivastava},
url = {https://doi.org/10.1063/1.5032653},
doi = {https://doi.org/10.1063/1.5032653},
year = {2018},
date = {2018-05-08},
urldate = {2018-05-08},
journal = {AIP Conference Proceedings},
volume = {1953},
issue = {1},
pages = {040033},
abstract = {We have studied structural phase transition and electronic properties of CdTe nanowires in their wurtzite (B4) to rocksalt (B1) phase by first principles density functional calculations using SIESTA code. Nanowires are derived from wurtzite and rocksalt phase of bulk CdTe with growth direction along 100 planes. We observed structural phase transition from B4→B1 at 4.79 GPa. Wurtzite structure is found to have band gap 2.30 eV while rocksalt is metallic in nature. Our calculated lattice constant (4.55 Å for B4 and 5.84 Å for B1), transition pressure (4.79 GPa) and electronic structure results are in close agreement with the previous calculations on bulk and nanostructures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We have studied structural phase transition and electronic properties of CdTe nanowires in their wurtzite (B4) to rocksalt (B1) phase by first principles density functional calculations using SIESTA code. Nanowires are derived from wurtzite and rocksalt phase of bulk CdTe with growth direction along 100 planes. We observed structural phase transition from B4→B1 at 4.79 GPa. Wurtzite structure is found to have band gap 2.30 eV while rocksalt is metallic in nature. Our calculated lattice constant (4.55 Å for B4 and 5.84 Å for B1), transition pressure (4.79 GPa) and electronic structure results are in close agreement with the previous calculations on bulk and nanostructures.
2017
Bhatia, Manjeet; Srivastava, Anurag
Bandgap and magnetic moment of Ga1-xCrxN Journal Article
In: AIP Conference Proceedings, vol. 1832, iss. 1, pp. 090045, 2017.
@article{nokey,
title = {Bandgap and magnetic moment of Ga1-xCrxN},
author = {Manjeet Bhatia and Anurag Srivastava},
url = {https://doi.org/10.1063/1.4980598},
doi = {https://doi.org/10.1063/1.4980598},
year = {2017},
date = {2017-05-19},
urldate = {2017-05-19},
booktitle = {AIP Conference Proceedings },
journal = {AIP Conference Proceedings},
volume = {1832},
issue = {1},
pages = {090045},
publisher = {AIP Publishing LLC},
abstract = {We report a DFT based ab-initio analysis of ground state properties, electronic structure and magnetic properties Cr (25%, 50% and 75%) doped GaN compound in its zincblende phase. It is observed that bulk modulus is found to decrease with increasing Cr concentration. The semiconducting GaN transforms to metallic due to introduction of Chromium at the site of Ga in GaN. The computed electronic density shows a half-metallic behavior of a doped compound with a magnetic moment of 3 µB/ Cr-atom.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report a DFT based ab-initio analysis of ground state properties, electronic structure and magnetic properties Cr (25%, 50% and 75%) doped GaN compound in its zincblende phase. It is observed that bulk modulus is found to decrease with increasing Cr concentration. The semiconducting GaN transforms to metallic due to introduction of Chromium at the site of Ga in GaN. The computed electronic density shows a half-metallic behavior of a doped compound with a magnetic moment of 3 µB/ Cr-atom.
2014
Bhatia, Manjeet Kumar; Gangineni, RB
Electronic transport across a layered structure of Fe/beta-poly vinylidene fluoride/Fe using DFT calculations Journal Article
In: Journal of Computational Electronics, vol. 13, iss. 3, pp. 613-619, 2014.
@article{Bhatia2014,
title = {Electronic transport across a layered structure of Fe/beta-poly vinylidene fluoride/Fe using DFT calculations},
author = {Manjeet Kumar Bhatia and RB Gangineni},
url = {https://doi.org/10.1007/s10825-014-0578-8},
doi = {https://doi.org/10.1007/s10825-014-0578-8},
year = {2014},
date = {2014-06-03},
urldate = {2014-06-03},
journal = {Journal of Computational Electronics},
volume = {13},
issue = {3},
pages = {613-619},
abstract = {Quantum electronic transport across a -poly(vinylidene fluoride) (-PVDF) ferroelectric barrier structured between two ferromagnetic Fe layers is explored using DFT calculations. The multifunctional junction is organized in capacitor like structure, as FM (ferromagnetic metal)/FE (ferroelectric)/FM to understand the mechanism of electron transfer by controlling the spin polarization of the electrodes and also the ferroelectric polarization of the barrier. These studies are carried on a single bcc layer of Fe atoms in both the electrodes and two monomers of PVDF is utilized as a barrier. We investigated the dependence of total density of states (DOS), projected DOS, transmission coefficient and I–V characteristics on applied bias voltage using SIESTA & TRANSIESTA package.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Quantum electronic transport across a -poly(vinylidene fluoride) (-PVDF) ferroelectric barrier structured between two ferromagnetic Fe layers is explored using DFT calculations. The multifunctional junction is organized in capacitor like structure, as FM (ferromagnetic metal)/FE (ferroelectric)/FM to understand the mechanism of electron transfer by controlling the spin polarization of the electrodes and also the ferroelectric polarization of the barrier. These studies are carried on a single bcc layer of Fe atoms in both the electrodes and two monomers of PVDF is utilized as a barrier. We investigated the dependence of total density of states (DOS), projected DOS, transmission coefficient and I–V characteristics on applied bias voltage using SIESTA & TRANSIESTA package.
Published Journals
Journal of Mass SSpectrometry
Journal of American Society for Mass SSpectrometry
International Journal of Mass Spectrometry
Computational and Theoretical Chemistry
Computational Toxicology
