title: Vibrational spectra, NLO analysis, and HOMO-LUMO studies of 2-chloro-6-fluorobenzoic acid and 3,4-dichlorobenzoic acid by density functional method.
abstract: The FTIR and FT-Raman spectra of 2-chloro-6-fluorobenzoic acid and 3,4-dichlorobenzoic acid have been recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of fundamental modes of the compounds were carried out. The optimized molecular geometries, vibrational frequencies, thermodynamic properties and atomic charge of the compounds were calculated by using density functional theory (B3LYP) method with 6-311+G and 6-311++G basis sets. The difference between the observed and scaled wave number values of most of fundamentals is very small. Unambiguous vibration assignment of all the fundamentals is made up the total energy distribution (TED). The calculated HOMO and LUMO energies show that charge transfer occurs within the molecules. Besides, molecular electro static potential (MESP), Mulliken's charge analysis, first order hyper polarizability and several thermodynamic properties were performed by the DFT method.
authors.affiliation: PG & Research Department of Physics, Periyar E.V.R College (Autonomous), Tiruchirappalli 620 023, India. Electronic address: josenthil74@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Senthil Kumar
authors.affiliation: Depatrment of Physics, Government Arts College, Tiruchirappalli 620 022, India.
authors.forename: M
authors.initials: M
authors.lastname: Arivazhagan
authors.affiliation: Department of Computer Application, Bishop Heber College (Autonomous) Tiruchirappalli 620 017, India.
authors.forename: P
authors.initials: P
authors.lastname: Thangaraju
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D002723:Chlorobenzoates / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
chemical_list: D001565:Benzoates; D002723:Chlorobenzoates; C068797:3,4-dichlorobenzoic acid; C022894:2-fluorobenzoic acid
keywords: 2-Chloro-6-fluorobenzoic acid; 3,4-Dichlorobenzoic acid; MESP; Mulliken charge; NLO