title: Natural bond orbital analysis, electronic structure, non-linear properties and vibrational spectral analysis of L-histidinium bromide monohydrate: a density functional theory.
abstract: The spectroscopic properties of the crystallized nonlinear optical molecule L-histidinium bromide monohydrate (abbreviated as L-HBr-mh) have been recorded and analyzed by FT-IR, FT-Raman and UV techniques. The equilibrium geometry, vibrational wavenumbers and the first order hyperpolarizability of the crystal were calculated with the help of density functional theory computations. The optimized geometric bond lengths and bond angles obtained by using DFT (B3LYP/6-311++G(d,p)) show good agreement with the experimental data. The complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The natural bond orbital (NBO) analysis confirms the occurrence of strong intra and intermolecular N-H⋯O hydrogen bonding.
authors.affiliation: Department of Physics, Bishop Moore College, Mavelikara, Alappuzha 690110, Kerala, India. drsajanbmc@gmail.com
authors.forename: D
authors.initials: D
authors.lastname: Sajan
authors.forename: Lynnette
authors.initials: L
authors.lastname: Joseph
authors.forename: N
authors.initials: N
authors.lastname: Vijayan
authors.forename: M
authors.initials: M
authors.lastname: Karabacak
mesh_terms: D001965:Bromides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004583:Electrons; D006639:Histidine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D017711:Nonlinear Dynamics; D009904:Optical Rotation; D011789:Quantum Theory; D012399:Rotation; D013057:Spectrum Analysis; D055672:Static Electricity; D014732:Vibration; D014867:Water / Q000737:chemistry
chemical_list: D001965:Bromides; D014867:Water; D006639:Histidine