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Xavier R.J.,Periyar EVR College Autonomous
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The complete vibrational assignment and analysis of the fundamental modes of 2-bromo-5-nitrothiazole (BNT) was carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the ab initio HF and DFT-B3LYP gradient calculations employing 6-311++G(d,p) basis set. Thermodynamic properties like entropy, heat capacity and zero point energy have been calculated for the molecule. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis. Important non-linear properties such as electric dipole moment and first hyperpolarizability of BNT have been computed using B3LYP quantum chemical calculation. © 2012 Elsevier B.V. All rights reserved.


John Xavier R.,Periyar EVR College Autonomous | Ashok Raj S.,Government Arts College Autonomous
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The 4-morpholine carbonitrile (4MC) was investigated by vibrational spectroscopy and quantum chemical methods. The solid phase FT-IR and FT-Raman spectra were recorded in the region 4000-400 cm-1 and 3500-50 cm -1, respectively. The molecular geometry and vibrational frequencies of 4MC have been calculated in the ground state by using the ab initio Hartree-Fock and density functional method (B3LYP) with 6-311++G(d, p) basis set. The observed and calculated frequencies are found to be in good agreement. The calculated HOMO and LUMO energies show the charge transfer occurs within the molecule. Stability of the molecule arising from hyper conjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The theoretical FT-IR and FT-Raman spectra for the title compound have also been constructed. © 2012 Published by Elsevier B.V. All rights reserved.


John Xavier R.,Periyar EVR College Autonomous
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The FT-IR and FT-Raman spectra of 4-pyridinecarbohydrazide have been recorded. The complete vibrational assignment and analysis of the fundamental modes was carried out using the experimental data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the DFT-B3LYP gradient calculations employing 6-311++G(d,p) basis set. The 1H and 13C NMR chemical shifts have been simulated. Thermodynamic properties have been calculated at different temperatures. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis. © 2013 Elsevier B.V. All rights reserved.


Xavier R.J.,Periyar EVR College Autonomous
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

The molecular vibrations of o-chlorobenzohydrazide (OCBH) have been investigated in polycrystalline sample, at room temperature, by recording Fourier transform infrared (FT-IR) and FT-Raman spectroscopies. The complete vibrational assignment and analysis of the fundamental modes was carried out using the experimental data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the HF and DFT/B3LYP calculations employing 6-311++G(d,p) basis set. The 1H and 13C NMR chemical shifts have been simulated. Thermodynamic properties have been calculated at different temperatures. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis. © 2014 Elsevier B.V. All rights reserved.


Sakthi Velu A.,Periyar EVR College Autonomous
Journal of Materials Science: Materials in Electronics | Year: 2016

Copper (Cu) and iron (Fe) doped zinc oxide (ZnO) nanoparticles (NPs) were synthesized by co-precipitation method. The average crystallite sizes of the synthesized NPs were found to be 28 and 30 nm for Cu and Fe doped ZnO NPs respectively. From FESEM images, Cu and Fe doped ZnO NPs showed that the spherical structure morphology. The amount of dopant (Cu2+ and Fe3+) ions incorporated with ZnO NPs was determined by EDAX. FT-IR spectra confirmed the presence of Zn–O stretching bands at 438, 416 and 431 cm−1 in the respective ZnO NPs. Optical absorption spectra revealed the estimated band gap was found to increase for Cu and Fe doped ZnO NPs as compared to the pure ZnO NPs. The photoluminescence measurements revealed the broad emissions were composed seven different bands due to zinc vacancies, oxygen vacancies and surface defects. © 2016 Springer Science+Business Media New York

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