title: Structure and nonlinear optical property analysis of L-Methioninium oxalate: a DFT approach.
abstract: Infrared and FT-Raman spectra of the nonlinear optical material l-Methioninium Oxalate were recorded and analyzed. The optimized geometry, first-order hyperpolarizability and harmonic vibrational wavenumbers were calculated with the help of density functional theory method. The detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis followed by scaled quantum mechanical force field methodology. Stability of the molecule arising from hyperconjugative interactions leading to its nonlinear optical activity and charge delocalization were analyzed using natural bond orbital technique. Mulliken atomic charge and molecular electrostatic potential are also predicted. HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. The thermodynamic properties at different temperatures are also calculated.
authors.affiliation: Department of Physics, Muslim Arts College, Thiruvithancode 629 174, Tamil Nadu, India; Department of Physics, Women's Christian College, Nagercoil 629 001, Tamil Nadu, India.
authors.forename: G Edwin
authors.initials: GE
authors.lastname: Sheela
authors.affiliation: Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, Kerala, India.
authors.forename: D
authors.initials: D
authors.lastname: Manimaran
authors.affiliation: Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, Kerala, India. Electronic address: hubertjoe@gmail.com.
authors.forename: I
authors.initials: I
authors.lastname: Hubert Joe
authors.affiliation: Department of Chemistry, St. John's College, Anchal, Kollam 691 306, Kerala, India.
authors.forename: Sherifa
authors.initials: S
authors.lastname: Rahim
authors.affiliation: Department of Physics, Women's Christian College, Nagercoil 629 001, Tamil Nadu, India.
authors.forename: V Bena
authors.initials: VB
authors.lastname: Jothy
mesh_terms: D008715:Methionine / Q000031:analogs & derivatives* / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
chemical_list: C000604630:L-methioninium oxalate; D008715:Methionine
keywords: DFT; FT-Raman; FTIR; HOMO–LUMO; NLO