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Srinivasan P.,C Kandaswami Naidu College For Men | Stephen A.D.,Coimbatore Institute of Technology
Journal of Theoretical and Computational Chemistry | Year: 2015

The electron density and conductivity studies of 2,5-diphenyl-1,3,4-oxadizole organic light emitting diode (OLED) based molecule have been calculated from the quantum chemical calculations and combined with the Bader's AIM theory. Density functional theory calculations with B3LYP/aug-cc-PVDZ basis sets was used to determine ground state gas space molecular geometries (bond lengths and bond angles), electron density and bonding features of this molecule. The electron densities at the bond critical point (BCP) of aromatic Car-Car bonds are much stronger than the other bonds in the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The HOMO-LUMO gap calculated from quantum chemical calculations has been compared with the value calculated from the density of states. The negative electrostatic potential (ESP) is concentrated solely around the N atoms, whereas in the rest of the region a positive ESP to dominate. © 2015 World Scientific Publishing Company. Source


Gnanasekaran P.,Loyola College | Gnanasekaran P.,C Kandaswami Naidu College For Men | Madhavan J.,Loyola College
Asian Journal of Chemistry | Year: 2010

Single crystals of pure and lanthanum doped L-alanine acetate were grown successfully by slow evaporation technique. The grown crystals were confirmed by X-ray powder diffraction studies. The pure and doped crystals were characterized by Fourier transform infrared (FT-1R) and UV-Vis-NIR studies. It was found that the optical properties were enhanced by the incorporation of the dopant. Hardness studies were also carried out for the grown crystals. Non-linear optical studies reveal that the dopant has increased the efficiency of the L-alanine acetate crystal. Source


Gnanasekaran P.,Loyola College | Gnanasekaran P.,C Kandaswami Naidu College For Men | Madhavan J.,Loyola College
Asian Journal of Chemistry | Year: 2010

Single crystals of pure and La3+ doped L-arginine acetate have been successfully grown from aqueous solution by slow evaporation technique. The grown crystals were confirmed by powder X-ray diffraction studies. The optical properties of the crystals were studied by FT-IR and UV-Vis-NIR spectral techniques and the influence of the La3+ is reported. The second harmonic generation efficiencies of the crystals were confirmed by Kurtz and Perry powder technique. Source


Latha B.,Dr. M.G.R. Educational and Research Institute | Latha B.,University | Gunasekaran S.,St Peters University | Srinivasan S.,Presidency College at Chennai | Ramkumaar G.R.,C Kandaswami Naidu College For Men
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

The solid phase FTIR and FT-Raman spectra of Losartan have been recorded in the region 400-4000 cm-1. The spectra were interpreted in terms of fundamental modes, combination and overtone bands. The structure of the molecule was optimized and the structural characteristics were determined by Quantum chemical methods. The vibrational frequencies yield good agreement between observed and calculated values. The infrared and Raman spectra were also predicted from the calculated intensities. (1)H and (13)C NMR spectra were recorded and resonance chemical shifts of the molecule were calculated. UV-Visible spectrum of the compound was recorded in the region 200-600 nm and the electronic properties HOMO and LUMO energies calculated by TD-HF approach. NBO atomic charges of the molecules and second order perturbation theory analysis of Fock matrix also calculated and interpreted. The geometrical parameters, energies, harmonic vibrational frequencies, IR intensities, Raman intensities, and absorption wavelengths were compared with experimental and theoretical data of the molecule. © 2014 Elsevier B.V. All rights reserved. Source


Ramya T.,Ctte College For Women | Ramya T.,Pachaiyappas College | Gunasekaran S.,St Peters University | Ramkumaar G.R.,C Kandaswami Naidu College For Men
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2015

The experimental and theoretical spectra of (S)-2-Oxopyrrolidin-1-yl Butanamide (S2OPB) were studied. FT-IR and FT-Raman spectra of S2OPB in the solid phase were recorded and analyzed in the range 4000-450 and 5000-50 cm-1 respectively. The structural and spectroscopic analyses of S2OPB were calculated using ab initio Hartree Fock (HF) and density functional theory calculations (B3PW91, B3LYP) with 6-31G(d,p) basis set. A complete vibrational interpretation has been made on the basis of the calculated Potential Energy Distribution (PED). The HF, B3LYP and B3PW91 methods based NMR calculation has been used to assign the 1H NMR and 13C NMR chemical shift of S2OPB. Comparative study on UV-Vis spectral analysis between the experimental and theoretical (B3PW91, B3LYP) methods and the global chemical parameters and local descriptor of reactivity through the Fukui function were performed. Finally the thermodynamic properties of S2OPB were calculated at different temperatures and the corresponding relations between the properties and temperature were also studied. © 2015 Elsevier B.V. Source

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