title: Ab-initio and density functional study of L- and D-forms of alanine and serine in gas phase and bulk aqueous medium.
abstract: The molecular geometry of L and D-forms of alanine and serine in gas phase have been studied by using ab-initio quantum chemical calculations at the restricted Hartree-Fock (RHF) level by employing 6-31G and 6-311++G** basis sets. Subsequently, for considering the electron correlations, Density functional Calculations at the Becke3LYP (B3LYP) and Moller-Plesset second order (MP2) level of calculations have been carried out with the same basis sets for these optimized geometries. Effect of solvation in water on the optimized geometries was studied using the polarized continuum model of the self-consistent reaction field (SCRF) theory. The dipole moment, energy, polarizabilities and vibrational frequencies have been calculated in all cases. Frequency analysis was carried out to ensure that optimized geometry corresponds to a total energy minimum.
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, B.H.U., Varanasi 221005, Uttar Pradesh, India. dmupadhyay@rediffmail.com
authors.forename: D M
authors.initials: DM
authors.lastname: Upadhyay
authors.forename: Amareshwar Kumar
authors.initials: AK
authors.lastname: Rai
authors.forename: D K
authors.initials: DK
authors.lastname: Rai
authors.forename: A N
authors.initials: AN
authors.lastname: Singh
authors.forename: Anup
authors.initials: A
authors.lastname: Kumar
mesh_terms: D000409:Alanine / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D008956:Models, Chemical; D012694:Serine / Q000737:chemistry*; D012996:Solutions; D055672:Static Electricity; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D005740:Gases; D012996:Solutions; D012694:Serine; D000409:Alanine