title: Density functional theory, comparative vibrational spectroscopic studies, HOMO-LUMO, first hyperpolarizability analyses of 2-fluoro 5-nitrotoluene and 2-bromo 5-nitrotoluene.
abstract: This work deals with the vibrational spectra of 2-fluoro 5-nitrotoluene and 2-bromo 5-nitrotoluene by quantum chemical calculations. The solid phase FTIR and FT-Raman spectra of the title compounds were recorded in the regions 4000-400 cm(-1) and 4000-50 cm(-1) respectively. The spectra were interpreted with the aid of normal co-ordinate analysis based on density functional theory (DFT) using standard B3LYP/6-31G(*) basis set for the most optimized geometry. The vibrational frequencies are calculated and scaled values are compared with experimental FTIR and FT-Raman spectra. The scaled theoretical wave numbers showed very good agreement with the experimental ones. The complete vibrational assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. (13)C and (1)H NMR chemical shifts results are compared with the experimental values.
authors.affiliation: Department of Physics, Periyar University, Salem 636 011, India. vkrishna_kumar@yahoo.com
authors.forename: V
authors.initials: V
authors.lastname: Krishnakumar
authors.forename: R
authors.initials: R
authors.lastname: Sangeetha
authors.forename: R
authors.initials: R
authors.lastname: Mathammal
authors.forename: D
authors.initials: D
authors.lastname: Barathi
mesh_terms: D003198:Computer Simulation; D007700:Kinetics; D016014:Linear Models; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014050:Toluene / Q000031:analogs & derivatives* / Q000737:chemistry*; D014732:Vibration
chemical_list: C582187:2-bromo 5-nitrotoluene; C582186:2-fluoro 5-nitrotoluene; D014050:Toluene