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Amalanathan M.,Center for Molecular and Biophysics Research | Joe I.H.,Center for Molecular and Biophysics Research | Kostova I.,Medical University-Sofia
Journal of Raman Spectroscopy | Year: 2010

The Fourier transform infrared (4000-400 cm-1) and Fourier transform Raman (3500-500 cm-1) spectra of 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one (Warfarin) have been measured and calculated. The structure optimization has been made using density functional theory (DFT) calculations. Complete vibrational assignments of the observed spectra have been compared with theoretical wavenumbers. The wavenumber increasing in the methyl group shows the electronic hyperconjugation effect. The natural bond orbital (NBO) analysis reveals the hyperconjugation interaction and the intramolecular hydrogen bonding. The first-order hyperpolarizability has been calculated. © 2009 John Wiley & Sons, Ltd.

Amalanathan M.,Center for Molecular and Biophysics Research | Hubert Joe I.,Center for Molecular and Biophysics Research | Rastogi V.K.,University Campus
Journal of Molecular Structure | Year: 2011

FT-IR and Raman spectra of the nonlinear optical material l-Valine Hydrobromide crystal have been recorded and analyzed. The equilibrium geometry, bonding features and the harmonic vibrational wavenumbers of LVB have been calculated with the help of density functional theory (DFT) calculation. The lowering of NH stretching wavenumber indicates the formation of NH⋯Br hydrogen bonding. The calculated First order hyperpolarizability value shows that LVB is the potential candidate for the NLO applications. The electronic effects and the hydrogen bonding were explained using natural bond orbital analysis. © 2010 Published by Elsevier B.V.

Leenaraj D.R.,Center for Molecular and Biophysics Research | Joe I.H.,Center for Molecular and Biophysics Research
Materials Today: Proceedings | Year: 2015

FT-IR spectra of Lidocaine compound have been recorded and analyzed. Density fuctional theoretical computations are performed at B3LYP/6-311+G(d,p) level to derive optimizd geometry, bonding features and harmonic vibrational wavenumbers. The calculated geometrical parameters have been compared with experimental data. The detailed interpretation of the vibrational spectra assignment has been carried out on the basis of potential energy distribution analysis using VEDA4 program. The Natural Bond Orbital (NBO) analysis confirms the occurrence of strong intramolecular N-H···N hydrogen bond in the molecule. The Mulliken population analysis and the HOMO-LUMO energy were also studied. © 2015 Elsevier Ltd.

Sabitha C.,Center for Molecular and Biophysics Research | Joe I.H.,Center for Molecular and Biophysics Research
Materials Today: Proceedings | Year: 2015

Highly transparent and adherent ZnS thin films were grown on the glass substrate by spin coating method using an aqueous solution containing zinc sulfate and Polymethylmethacrylate in Tetrahedrafuran as a solvent. The films were characterized by X-ray diffraction, Scanning electron microscopy and UV-Vis spectroscopy techniques. The X-ray diffraction pattern shows the highest reflection peak at d=3.09. Å (111). The diffraction angles and plane were (28.77) (111), (33.22) (200), (47.76) (220) and (56.62) (311) respectively. The particle size was found to be at around 35. nm. The optical band gap values calculated for the film is 4.12. eV. The UV- spectra reveal that films have low absorbance in the visible and near infrared regions. However the absorbance in the ultraviolet region is high. The enhanced absorption is observed in the neighborhood of λ=360nm. The SEM morphologies of the films revealed semispherical structure formed by the smaller particle on the ZnS film surface. Self-assembly of grains are observed in the AFM image of the film. © 2015 Elsevier Ltd.

Kuriakose S.,Center for Molecular and Biophysics Research | Joe I.H.,Center for Molecular and Biophysics Research
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Determination of the authenticity of essential oils has become more significant, in recent years, following some illegal adulteration and contamination scandals. The present investigative study focuses on the application of near infrared spectroscopy to detect sample authenticity and quantify economic adulteration of sandalwood oils. Several data pre-treatments are investigated for calibration and prediction using partial least square regression (PLSR). The quantitative data analysis is done using a new spectral approach - full spectrum or sequential spectrum. The optimum number of PLS components is obtained according to the lowest root mean square error of calibration (RMSEC = 0.00009% v/v). The lowest root mean square error of prediction (RMSEP = 0.00016% v/v) in the test set and the highest coefficient of determination (R2 = 0.99989) are used as the evaluation tools for the best model. A nonlinear method, locally weighted regression (LWR), is added to extract nonlinear information and to compare with the linear PLSR model. © 2013 Elsevier B.V. All rights reserved.

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