title: Molecular structure, vibrational spectroscopic, first order hyperpolarizability and HOMO-LUMO studies of 7-amino-8-oxo-3-vinyl-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.
abstract: The FT-IR and FT-Raman spectra of 7-amino-8-oxo-3-vinyl-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (7AVCA) were recorded in the region 4000-400 cm(-1) and 3500-10 cm(-1), respectively. Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers were carried out by ab initio HF and density functional theoretical methods invoking 6-311G(d,p) basis set. The differences between the observed and scaled wavenumber values of most of the fundamentals are very small. The electric dipole moment (μ) and the first order hyperpolarizability (β0) values have been computed quantum mechanically. The calculated results show that 7AVCA may have microscopic nonlinear optical (NLO) behavior with non-zero values. A detailed interpretation of the FT-IR and FT-Raman spectra of 7AVCA is reported. The theoretical IR and Raman spectra of 7AVCA have also been constructed. The calculated HOMO and LUMO energies show that the charge transfer occurs within the molecule.
authors.affiliation: CRD, PRIST University, Vallam, Thanjavur 613403, India. km_ramalingam@yahoo.co.in
authors.forename: M
authors.initials: M
authors.lastname: Ramalingam
authors.forename: V
authors.initials: V
authors.lastname: Sethuraman
authors.forename: N
authors.initials: N
authors.lastname: Sundaraganesan
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D014732:Vibration; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: C557921:7-amino-8-oxo-3-vinyl-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002264:Carboxylic Acids; D005030:Ethylenes; D014753:Vinyl Compounds; C036216:ethylene