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Wilson K.S.J.,Arul Anandar College Autonomous | Revathy V.,Arul Anandar College Autonomous | Lenin M.M.,Annai Velankanni College | Jothy V.B.,Womens Christian College
Materials Today: Proceedings | Year: 2015

The transmission properties of one dimensional photonic crystals with two defects having structures (HL)n(D1LD2L)m(HL)n, where m is the stack number of the Photonic Quantum Well (PQW) have been theoretically investigated by the transfer matrix method. The thickness and temperature dependence of the defect modes have been studied by considering Si and air as the high and low refractive index materials with GaAs and InSb as the two defects. For a defect lattice with m=1 (two defects) the two peaks due to defects are shifted towards the higher wavelength region, when the thickness of the defect layers is changed. Also, the transmittance peaks are shifted by 0.44. nm/K and 0.50. nm/K due to temperature variation. The above shifts for other cases (m ≠ 1 and n ≠ 1), have also been obtained. Part of these results is in qualitative agreement with the results available in the literature for other photonic crystals. © 2015 Elsevier Ltd.


Sylvestre S.,DMI-St. EUGENE University | Sebastian S.,Sri Manakula Vinayagar Engg College | Edwin S.,DMI-St. EUGENE University | Amalanathan M.,Annai Velankanni College | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

In this work we report the vibrational spectral analysis of l-Asparagine Monohydrate (LAM) molecule by using FT-IR and FT-Raman spectroscopic techniques. The equilibrium geometry, harmonic vibrational wavenumbers, various bonding features have been computed using density functional B3LYP method with 6-311G(d,p) as basis set. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in σ* and π* antibonding orbitals and second order delocalization energies E(2) confirms the occurrence of Intramolecular Charge Transfer (ICT) within the molecule. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental spectra. © 2014 Elsevier B.V. All rights reserved.


PubMed | Government College of Technology, Coimbatore, Annai Velankanni College, Government of Puducherry, DMI-St. EUGENE University and Sri Manakula Vinayagar Engg College
Type: | Journal: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy | Year: 2014

In this work we report the vibrational spectral analysis of l-Asparagine Monohydrate (LAM) molecule by using FT-IR and FT-Raman spectroscopic techniques. The equilibrium geometry, harmonic vibrational wavenumbers, various bonding features have been computed using density functional B3LYP method with 6-311G(d,p) as basis set. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in (*) and (*) antibonding orbitals and second order delocalization energies E((2)) confirms the occurrence of Intramolecular Charge Transfer (ICT) within the molecule. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental spectra.


Amalanathan M.,Annai Velankanni College | Sebastian S.,Sri Manakula Vinayagar Engg College | Sajan D.,Bishop Moore College | Hubert Joe I.,Center for Molecular and Biophysics Research | Bena Jothy V.,Womens Christian College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

Vibrational analysis of ethyl 4-nitrophenylacetate (ENPA) molecule was carried out using FT-IR and FT-Raman spectroscopic techniques. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional theory. The calculated molecular geometry parameters have been compared with XRD data. The detailed interpretation of the vibrational spectra has been carried out by computing Potential Energy Distribution (PED). Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. The results show that the charge in the electron density (ED) in the σ and π antibonding orbitals and second order delocalization energies (E2) confirm the occurrence of ICT (intramolecular charge transfer) within the molecule. The simulated spectra satisfactorily coincide with the experimental spectra. © 2012 Elsevier B.V. All rights reserved.


Amalanathan M.,Annai Velankanni College | Sebastian S.,Sri Manakula Vinayagar Engg College | Sajan D.,Bishop Moore College | Hubert Joe I.,Center for Molecular and Biophysics Research | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The molecular geometry, the normal mode frequencies and corresponding vibrational assignments, natural bond orbital analysis and the HOMO-LUMO analysis of 7-Amino-2,4-dimethylquinolinium formate in the ground state were performed by B3LYP levels of theory using the 6-31G(d) basis set. The optimised bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of the title compound which is calculated by DFT method, reproduces vibrational wave numbers and intensities with an accuracy which allows reliable vibrational assignments. The possibility of N- H···O hydrogen bonding was identified using NBO analysis. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. © 2013 The Authors.


Sebastian S.,Sri Manakula Vinayagar Engg College | Sylvestre S.,Achariya Arts and Science College | Jayarajan D.,Divine Mother College | Amalanathan M.,Annai Velankanni College | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

In this work, we report harmonic vibrational frequencies, molecular structure, NBO and HOMO, LUMO analysis of Umbelliferone also known as 7-hydroxycoumarin (7HC). The optimized geometric bond lengths and bond angles obtained by computation (monomer and dimmer) shows good agreement with experimental XRD data. Harmonic frequencies of 7HC were determined and analyzed by DFT utilizing 6-311+G(d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of Normal Coordinate Analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). The change in electron density (ED) in the σ* and π* antibonding orbitals and stabilization energies E(2) have been calculated by Natural Bond Orbital (NBO) analysis to give clear evidence of stabilization originating in the hyperconjugation of hydrogen-bonded interaction. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincides with the experimental spectra. Microbial activity of studied compounds was tested against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Psuedomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Shigella flexneri, Salmonella typhi and Enterococcus faecalis. © 2012 Published by Elsevier B.V. All rights reserved.


Sebastian S.,Sri Manakula Vinayagar Engg College | Sylvestre S.,Achariya Arts and Science College | Sundaraganesan N.,Annamalai University | Amalanathan M.,Annai Velankanni College | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Vibrational spectral analysis of 4-amino-3-hydroxy-1- naphthalenesulfonicacid (4A3HNSA) molecule were carried out using FT-IR and FT-Raman spectroscopic techniques. The equilibrium geometry, harmonic vibrational wavenumbers, various bonding features have been computed using density functional B3LYP method with 6-31G(d,p) as basis set. The Non-Linear Optical (NLO) behavior of 4A3HNSA has been studied by determination of the electric dipole moment (μ) and hyperpolarizability β using HF/6-31G(d,p) method. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in σ and π antibonding orbitals and second order delocalization energies (E2) confirms the occurrence of Intramolecular Charge Transfer (ICT) within the molecule. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental spectra. © 2013 Elsevier B.V. All rights reserved.


Rejo Jeice A.,Annai Velankanni College | Gerardin Jayam S.,Holy Cross College | Joseph Wilson K.S.,ArulAnandar College Autonomous
Chinese Physics B | Year: 2015

Simultaneous effect of hydrostatic pressure and polaronic mass on the binding energies of the ground and excited states of an on-center hydrogenic impurity confined in a GaAs/GaAlAs spherical quantum dot are theoretically investigated by the variational method within the effective mass approximation. The binding energy is calculated as a function of dot radius and pressure. Our findings proved that the hydrostatic pressure led to the decrease of confined energy and the increase of donor binding energy. Conduction band non-parabolicity and the polaron masses are effective in the donor binding energy which is significant for narrow dots not in the confined energy. The maximum donor binding energy achieved by the polaronic mass in the ground and excited states are 2%-19% for the narrow dots. The confined and donor binding energies approach zero as the dot size approaches infinity. © 2015 Chinese Physical Society and IOP Publishing Ltd.


Jeice A.R.,Annai Velankanni College | Jayam S.G.,Holy Cross College | Wilson K.S.J.,Arul Anandar College Autonomous
Indian Journal of Physics | Year: 2016

The binding energy and diamagnetic susceptibility of a hydrogenic donor in nanostructures like quantum well, quantum wire and quantum dot have been calculated for the finite and infinite barrier square well potential and are computed using variational technique. The binding energy of cubic nanostructures formed by GaAs/Ga1−xAlxAs has also been obtained using conduction band non-parabolicity and polaronic correction. Our results demonstrate that the effect of polaronic mass and band non-parabolicity which exhibits effective binding energy and diamagnetic susceptibility for the nanostructures having narrow width sizes and it is not significant to the low dimensional nanostructures. © 2016, Indian Association for the Cultivation of Science.


Jasmine G.F.,Bethlahem Institute of Engineering | Amalanathan M.,Annai Velankanni College | Roy S.D.D.,NMCC
Journal of Molecular Structure | Year: 2016

The Charge transfer contributions to the second-order nonlinear optical properties of 2-Methyl-4-nitroaniline have been performed by means of DFT computation. The vibrational contribution studies of 2-Methyl-4-nitroaniline have also been performed using FTIR, FT-Raman analysis. More support on the experimental findings were added from the quantum chemical studies performed with DFT (B3LYP) method using 6-311++G(d,p)basis sets. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. The HOMO and LUMO analysis reveals the possibility of charge transfer within the molecule. The first order hyperpolarizability (α0) and related properties (β,α0 and Δα) of 2-Methyl-4-nitroaniline were calculated. In addition, molecular electrostatic potential (MEP), charge analysis also were investigated using theoretical calculations. © 2016 Elsevier B.V. All rights reserved.

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