title: Quantum mechanical study of the structure and spectroscopic (FTIR, FT-Raman), first-order hyperpolarizability and NBO analysis of 1,2-benzoxazol-3-ylmenthane sulfonamide.
abstract: Fourier transform infrared (FTIR) and FT-Raman spectra of 1,2-benzoxazol-3-ylmenthane sulfonamide in the solid phase were recorded and analyzed. The molecular geometry, vibrational frequencies, infrared intensities, Raman activities and atomic charges were calculated using HF and density functional theory calculation (B3LYP) with standard 6-31G(d, p) basis set. Complete vibrational assignment and analysis of the fundamental modes of the compound were carried out using the observed FTIR and FT-Raman spectra. The thermodynamic functions of the title compound were also performed. Stability of the molecule arising from hyper-conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The dipole moment (μ), polarizability (α) and the hyperpolarizability (β) values of the molecule has been computed. Potential Energy Distribution (PED) were computed for the assignment of unambiguous vibrational fundamental modes. UV-vis spectrum of the compound was also recorded. The theoretical electronic absorption spectra have been calculated by TD-DFT/B3LYP using 6-31G(d,p) basis set. The HOMO and LUMO energy gap reveals that the chemical activity of the molecule. The molecular orbital contributions were studied by density of energy states (DOSs). Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. Finally, simulated FTIR and FT-Raman spectra of 1,2-benzoxazol-3-ylmenthane sulfonamide showed good agreement with the observed spectra.
authors.affiliation: Department of Physics, Sri Venkateswara College of Engineering, Sriperumbudur 602 105, Tamil Nadu, India. Electronic address: muthu@svce.ac.in.
authors.forename: S
authors.initials: S
authors.lastname: Muthu
authors.affiliation: Research Scholar Research and Development Centre, Bharathiyar University, Coimbatore, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Ramachandran
authors.affiliation: Department of Applied Physics, Pallavan College of Engineering, Kancheepuram 631 502, Tamil Nadu, India.
authors.forename: E
authors.initials: E
authors.lastname: Isac Paulraj
authors.affiliation: Department of Chemical Engineering, Sri Venkateswara College of Engineering, Sriperumbudur 602 105, Tamil Nadu, India.
authors.forename: T
authors.initials: T
authors.lastname: Swaminathan
mesh_terms: D015394:Molecular Structure; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D013449:Sulfonamides
keywords: DFT; FT-Raman; FTIR; NBO; PED