Thomas Kuruvilla - Academia.edu (original) (raw)
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Advanced Telecommunications Research Institute International
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Papers by Thomas Kuruvilla
Physics Letters A, 1999
The effect of coupling on two high frequency modulated semiconductor lasers is numerically studie... more The effect of coupling on two high frequency modulated semiconductor lasers is numerically studied. The phase diagrams and bifurcation diagrams are drawn. As the coupling constant is increased the system goes from chaotic to periodic behavior through a reverse period doubling sequence. The Lyapunov exponent is calculated to characterize chaotic and periodic regions.
Indian Journal of Physics, 2011
The comparative study of normal Raman spectrum with the SERS along with the DFT calculations pred... more The comparative study of normal Raman spectrum with the SERS along with the DFT calculations predicts the adsorption geometry of plumbagin on silver surface. The surface geometry of plumbagin molecule was studied by analysis of the SERS spectra adsorbed on silver colloid surfaces. The large enhancement of inplane ring stretching and C-H in-plane bending modes in the surface-enhanced Raman scattering spectrum indicates that the molecule is adsorbed on the silver surface in a stand-on orientation of PLBN on a silver surface.
Pramana, 2000
The effect of coupling two chaotic Nd:YAG lasers with intracavity KTP crystal for frequency doubl... more The effect of coupling two chaotic Nd:YAG lasers with intracavity KTP crystal for frequency doubling is numerically studied for the case of the laser operating in three longitudinal modes. It is seen that the system goes from chaotic to periodic and then to steady state as the coupling constant is increased. The intensity time series and phase diagrams are drawn and the Lyapunov characteristic exponent is calculated to characterize the chaotic and periodic regions.
Chaos: An Interdisciplinary Journal of Nonlinear Science, 1999
Single crystals of p-hydroxybenzaldehyde (PHBA) were grown by the slow evaporation technique and ... more Single crystals of p-hydroxybenzaldehyde (PHBA) were grown by the slow evaporation technique and vibrational spectral analysis was carried out using near-IR Fourier transform Raman and Fourier transform IR spectroscopy. The density functional theoretical (DFT) computations were also performed at the B3LYP/6-311++G(d,p) level to derive the equilibrium geometry, vibrational wavenumbers and intensities. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The various intramolecular interactions that is responsible for the stabilization of the molecule was revealed by natural bond orbital analysis. Vibrational analysis based on the NIR-FT-Raman, FT-IR and computed spectrum reveals that the CH in-plane bending of the aldehyde group interacts with its stretching mode via Fermi Resonance and evidence for intermolecular interaction can be well identified as two CH bands in IR spectra at 2740 and 2804 cm À1 aldehyde group of the p-hydroxybenzaldehyde dimer. The red shift of the O-H stretching wavenumber is due to the formation of strong O-HÁ Á ÁO hydrogen bonds by hyperconjugation between the carbonyl oxygen lone electron pairs and the O-H r à anti-bonding orbitals.
Physics Letters A, 1999
The effect of coupling on two high frequency modulated semiconductor lasers is numerically studie... more The effect of coupling on two high frequency modulated semiconductor lasers is numerically studied. The phase diagrams and bifurcation diagrams are drawn. As the coupling constant is increased the system goes from chaotic to periodic behavior through a reverse period doubling sequence. The Lyapunov exponent is calculated to characterize chaotic and periodic regions.
Indian Journal of Physics, 2011
The comparative study of normal Raman spectrum with the SERS along with the DFT calculations pred... more The comparative study of normal Raman spectrum with the SERS along with the DFT calculations predicts the adsorption geometry of plumbagin on silver surface. The surface geometry of plumbagin molecule was studied by analysis of the SERS spectra adsorbed on silver colloid surfaces. The large enhancement of inplane ring stretching and C-H in-plane bending modes in the surface-enhanced Raman scattering spectrum indicates that the molecule is adsorbed on the silver surface in a stand-on orientation of PLBN on a silver surface.
Pramana, 2000
The effect of coupling two chaotic Nd:YAG lasers with intracavity KTP crystal for frequency doubl... more The effect of coupling two chaotic Nd:YAG lasers with intracavity KTP crystal for frequency doubling is numerically studied for the case of the laser operating in three longitudinal modes. It is seen that the system goes from chaotic to periodic and then to steady state as the coupling constant is increased. The intensity time series and phase diagrams are drawn and the Lyapunov characteristic exponent is calculated to characterize the chaotic and periodic regions.
Chaos: An Interdisciplinary Journal of Nonlinear Science, 1999
Single crystals of p-hydroxybenzaldehyde (PHBA) were grown by the slow evaporation technique and ... more Single crystals of p-hydroxybenzaldehyde (PHBA) were grown by the slow evaporation technique and vibrational spectral analysis was carried out using near-IR Fourier transform Raman and Fourier transform IR spectroscopy. The density functional theoretical (DFT) computations were also performed at the B3LYP/6-311++G(d,p) level to derive the equilibrium geometry, vibrational wavenumbers and intensities. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The various intramolecular interactions that is responsible for the stabilization of the molecule was revealed by natural bond orbital analysis. Vibrational analysis based on the NIR-FT-Raman, FT-IR and computed spectrum reveals that the CH in-plane bending of the aldehyde group interacts with its stretching mode via Fermi Resonance and evidence for intermolecular interaction can be well identified as two CH bands in IR spectra at 2740 and 2804 cm À1 aldehyde group of the p-hydroxybenzaldehyde dimer. The red shift of the O-H stretching wavenumber is due to the formation of strong O-HÁ Á ÁO hydrogen bonds by hyperconjugation between the carbonyl oxygen lone electron pairs and the O-H r à anti-bonding orbitals.