Tagore Arts College

Puducherry, India

Tagore Arts College

Puducherry, India
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Ramalingam S.,Avc College | Anbusrinivasan P.,Avc College | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

In this work, the experimental and theoretical spectra of 4-chloro-2-bromoacetophenone (4C2BAP) are studied. FT-IR and FT-Raman spectra of title molecule have been recorded in the region 4000-100 cm-1. The structural and spectroscopic data of the molecule in the ground state have been calculated by using Hartree-Fock and density functional method (B3LYP) with the 6-31G (d, p) and 6-311G (d, p) basis sets. The vibrational frequencies are calculated and scaled values are compared with the experimental FT-IR and FT-Raman spectra. The DFT (B3LYP/6-311G (d, p)) calculations are more reliable than the ab initio HF/6-311G (d, p) calculations for the vibrational study of 4C2BAP. The optimized geometric parameters (bond lengths and bond angles) are compared with experimental values of the molecule. The alteration of vibrational bands of the carbonyl and acetyl groups due to the presence of halogens (Cl and Br) in the base molecule is also investigated from their characteristic region of linked spectrum. © 2010 Elsevier B.V. All rights reserved.


Govindarajan M.,MGGA College | Periandy S.,Tagore Arts College | Carthigayen K.,Bharathiyar University | Carthigayen K.,Dr Br Ambedkar Polytechnic College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4000 cm-1 and 50-4000 cm-1, respectively, for the title molecules. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartee Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The influences of bromine atom and methyl group on the geometry of benzene and its normal modes of vibrations have also been discussed. The results of the calculations were applied to simulated spectra of the title compounds, which show excellent agreement with observed spectra. © 2012 Elsevier B.V. All rights reserved.


Nagabalasubramanian P.B.,PRIST University | Karabacak M.,Afyon Kocatepe University | Periandy S.,Tagore Arts College
Journal of Molecular Structure | Year: 2012

The FT-IR and FT-Raman spectra of nicotinic acid ethyl ester (abbreviated as NAEE, C8H9NO2) have been recorded in the region 3600-10 cm-1. Potential energy curve was computed by means of scanning CCCO torsion angle. The optimized geometric parameters geometry optimization and the energies associated possible two conformers (C1 and C2) were computed. The computational results diagnose the most stable conformer of NAEE as the C1 form. The optimum molecular geometries, energies, normal mode wavenumbers, infrared and Raman intensities, corresponding vibrational assignments, atomic charges, HOMO-LUMO analysis and thermo-dynamical parameters were investigated with the help of HF, B3LYP and LSDA methods with 6-311G(d,p) and 6-311G++(d,p) basis sets. Reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanics (SQM) method. Thermodynamic properties of the title compound at different temperatures were calculated. The results of the calculations were applied to simulate infrared and Raman spectra of the title compound which show excellent agreement with the observed spectra. © 2012 Elsevier B.V. All rights reserved.


Govindarajan M.,MGGA College | Karabacak M.,Afyon Kocatepe University | Udayakumar V.,Thiru A Govindaswamy Arts College | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 100-4000 cm -1 and 400-4000 cm -1 respectively, for the title molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The effects due to the substitution of halogen bond were investigated. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), and thermodynamic properties were performed. The thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations between heat capacity (C), entropy (S), and enthalpy changes (H) and temperatures. © 2011 Elsevier B.V. All rights reserved.


Nagabalasubramanian P.B.,PRIST University | Karabacak M.,Afyon Kocatepe University | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

In this work, the FT-IR and FT-Raman spectrum of 1-(chloromethyl)-2-methyl naphthalene (abbreviated as 1-ClM-2MN, C 12H 11Cl) have been recorded in the region 3600-10 cm -1. The optimum molecular geometry, normal mode wavenumbers, infrared and Raman intensities, Raman scattering activities, corresponding vibrational assignments, Mullikan atomic charges and thermo-dynamical parameters were investigated with the help of HF and B3LYP (DFT) method using 6-311G(d,p), 6-311++G(d,p) basis sets. Also, the dipole moment, linear polarizabilities, anisotropy, first and second hyperpolarizabilities values were also computed using the same basis set. Reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method. The correlation equations between heat capacities, entropies, enthalpy changes and temperatures were fitted by quadratic formulas. Lower value in the HOMO and LUMO energy gap explains the eventual charge transfer interactions taking place within the molecule. UV-vis spectral analysis of 1-ClM-2MN has been researched by theoretical calculations. In order to understand the electronic transitions of the compound, TD-DFT calculations on electronic absorption spectra in gas phase and solvent (DMSO and chloroform) were performed. The calculated frontier orbital energies, absorption wavelengths (λ), oscillator strengths (f) and excitation energies (E) for gas phase and solvent are also illustrated. © 2011 Elsevier B.V. All rights reserved.


Nagabalasubramanian P.B.,PRIST University | Karabacak M.,Afyon Kocatepe University | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

In this work, the FT-IR and FT-Raman spectra of 1-naphthaleneacetic acid methyl ester (abbreviated as 1-NAAME, C 10H 7CH 2CO 2CH 3) have been recorded in the region 3600-10 cm -1. The optimum molecular geometry, normal mode wavenumbers, infrared and Raman intensities, Raman scattering activities, corresponding vibrational assignments, Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of HF and B3LYP (DFT) method using 6-31G(d,p), 6-311G(d,p) basis sets. Reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method. From the calculations, the molecules are predicted to exist predominantly as the C1 conformer. The correlation equations between heat capacity, entropy, enthalpy changes and temperatures were fitted by quadratic formulae. Lower value in the HOMO and LUMO energy gap explains the eventual charge transfer interactions taking place within the molecule. UV-VIS spectral analyses of 1NAAME have been researched by theoretical calculations. In order to understand electronic transitions of the compound, TD-DFT calculations on electronic absorption spectra in gas phase and solvent (DMSO and chloroform) were performed. The calculated frontier orbital energies, absorption wavelengths (λ), oscillator strengths (f) and excitation energies (E) for gas phase and solvent (DMSO and chloroform) are also illustrated. © 2011 Elsevier B.V. All rights reserved.


Nagabalasubramanian P.B.,Arignar Anna Government Arts College | Periandy S.,Tagore Arts College | Mohan S.,PRIST University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

The FT-IR and FT-Raman vibrational spectra of α-chlorotoluene have been recorded using Perkin-Elmer 180 spectrometer in the range 3600-10 cm -1 in the solid phase. A detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The optimized molecular geometry, vibrational frequencies, atomic charges, dipole moment, rotational constants and several thermodynamic parameters in the ground state were calculated using ab initio Hartree-Fock (HF) and Density Functional B3LYP methods (DFT) with 6-311G(d) and 6-311++G(d) basis sets. With the help of specific scaling procedures, the observed vibrational wavenumbers in FT-IR and FT-Raman spectra were analyzed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range. The results of the calculations were applied to simulated infrared and Raman spectra of the title compound which showed excellent agreement with the observed spectra. © 2010 Elsevier B.V.


Govindarajan M.,MGGA College | Karabacak M.,Afyon Kocatepe University | Suvitha A.,Periyar University | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4000 cm -1 and 50-4000 cm -1, respectively, for 4-chloro-3-nitrotoluene (C 7H 6NO 2Cl) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies shows that charge transfer within the molecule. The effects due to the substitutions of methyl group, nitro group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. © 2011 Elsevier B.V.


Ramalingam S.,Avc College Autonomous | Periandy S.,Tagore Arts College | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

The FTIR and FTRaman spectra of 2-amino pyridine (2-AP) molecule have been recorded using Bruker IFS 66 V spectrometer in the range of 4000-100 cm -1. The molecular geometry and vibrational frequencies in the ground state are calculated by using the ab initio Hartree-Fock (HF) and DFT (B3LYP and B3PW91) methods with 6-31++G (d, p) and 6-311++G (d, p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. Making use of the recorded data, the complete vibrational assignments are made and analysis of the observed fundamental bands of molecule is carried out. The geometries and normal modes of vibrations obtained from ab initio HF and B3LYP/B3PW91 calculations are in good agreement with the experimentally observed data. The differences between the observed and scaled wave number values of most of the fundamentals are very small in B3LYP than HF. The influence of N atom and amine group in the skeletal ring vibrations of the title molecule has also been discussed. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved.


Nagabalasubramanian P.B.,Arignar Anna Government Arts College | Periandy S.,Tagore Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

The FTIR and FT Raman vibrational spectra of 1,5-methylnaphthalene (1,5-MN) have been recorded using Brunker IFS 66 V Spectrometer in the range 3600-10 cm-1 in the solid phase. A detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The Optimized molecular geometry, harmonic frequencies, electronic polarizability, atomic charges, dipole moment, rotational constants and several thermodynamic parameters in the ground state were calculated using ab initio Hartree Fock (HF) and density functional B3LYP methods (DFT) with 6-311++ G(d) basis set. With the help of different scaling factors, the observed vibrational wavenumbers in FTIR and FT Raman spectra were analyzed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range. The results of the calculations were applied to simulated infrared and Raman spectra of the title compound which showed excellent agreement with the observed spectra. © 2010 Elsevier B.V. All rights reserved.

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