title: Theoretical investigation on vibrational spectra, first order hyperpolarizability and NBO analysis of 4-Phenylpyridinium hydrogen squarate.
abstract: The vibrational frequencies of 4-Phenylpyridinium hydrogen squarate (4PHS) in the ground state have been investigated by using B3LYP/6-311++G(d,p) level. The analysis of molecular structure, natural bond orbitals and frontier molecular orbitals was also performed. The IR spectra were obtained and interpreted by means of potential energies distributions (PEDs) using MOLVIB program. NBO analysis proved the presence of C-H⋯O and N-H⋯O hydrogen bonding interactions, which is consistent with the analysis of molecular structure. The dipole moments and first-order hyperpolarizability (βtot) are calculated and are 5.856 D and 4.72×10(-30) esu, respectively. The high βtot value and the low HOMO-LUMO energy gap (4.062eV) are responsible for the optical and electron-transfer properties of 4PHS molecule. The photoresponse-related results indicate that 4PHS molecule is an excellent organic candidate of photon-responsive materials.
authors.affiliation: College of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003, China; Luoyang Key Laboratory of Photoelectric Functional Materials, Henan University of Science and Technology, Luoyang 471023, China. Electronic address: lorna639@126.com.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Li
authors.affiliation: College of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Yong-Liang
authors.initials: YL
authors.lastname: Yong
authors.affiliation: College of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Hong-Ling
authors.initials: HL
authors.lastname: Cui
authors.affiliation: College of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Rui-Zhou
authors.initials: RZ
authors.lastname: Zhang
authors.affiliation: College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China.
authors.forename: Xian-Zhou
authors.initials: XZ
authors.lastname: Zhang
keywords: 4-Phenylpyridinium hydrogen squarate; Frontier molecular orbital; Hydrogen bonding interactions; Nonlinear optics; Vibrational spectrum