title: Electronic structure, vibrational spectral and intervening orbital interactions studies of NLO material: guanidinium 4-nitrobenzoate.
abstract: Single crystals of guanidinium 4-nitrobenzoate (GPNB) have been grown by slow evaporation method. Grown crystals were characterized by FT-IR, FT-Raman, UV-Vis absorption and UV-Vis transmission spectroscopies. Crystal defects and surface morphology were studied by etching method. Dielectric properties of the crystal such as dielectric constant, dielectric loss and AC electrical conductivity as function of frequency (50 Hz-5 MHz) at two temperatures (35°C and 100°C) were measured. The frequency and temperature dependence of dielectric behaviour were investigated. The equilibrium geometry, vibrational spectral analysis, intramolecular charge transfer interactions using NBO method, first order hyperpolarizability, molecular electrostatic potential and frontier molecular orbital analysis for GPNB have been studied using density functional theory at B3LYP/cc-pVTZ level. Vibrational spectral study reveals the presence of moderate and weak N-H⋯O bonds in GPNB. NBO analysis also confirms the presence of intramolecular N-H⋯O hydrogen bonding and investigates the stability as well as the intervening orbital interactions. The electronic absorption spectrum of the gas and water phases of GPNB were simulated using time dependent density functional theory and NBO transitions for the three lowest excited states were assigned and studied.
authors.affiliation: Post Graduate & Research Department of Physics, Bishop Moore College, Mavelikara, Kerala 690 110, India.
authors.forename: V
authors.initials: V
authors.lastname: Sasikala
authors.affiliation: Post Graduate & Research Department of Physics, Bishop Moore College, Mavelikara, Kerala 690 110, India. Electronic address: drsajanbmc@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Sajan
authors.affiliation: Post Graduate & Research Department of Physics, Bishop Moore College, Mavelikara, Kerala 690 110, India.
authors.forename: K Job
authors.initials: KJ
authors.lastname: Sabu
authors.affiliation: Post Graduate & Research Department of Physics, Pachaiyappa's College, Chennai 600 030, India.
authors.forename: T
authors.initials: T
authors.lastname: Arumanayagam
authors.affiliation: Post Graduate & Research Department of Physics, Pachaiyappa's College, Chennai 600 030, India.
authors.forename: P
authors.initials: P
authors.lastname: Murugakoothan
mesh_terms: D016880:Anisotropy; D004553:Electric Conductivity; D004583:Electrons; D019791:Guanidine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D009579:Nitrobenzoates / Q000737:chemistry*; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics; D014732:Vibration
chemical_list: D009579:Nitrobenzoates; C008629:4-nitrobenzoic acid; D019791:Guanidine
keywords: FT-IR; FT-Raman; Guanidinium 4-nitrobenzoate; NBO; NLO; Soft molecule