Vibrational investigation, molecular orbital studies and molecular electrostatic potential map analysis on 3-chlorobenzoic acid using hybrid computational calculations

Abstract

The FT-IR and FT-Raman spectra of 3-chlorobenzoic acid (3CBA) are recorded in the liquid state. The fundamental vibrational frequencies, intensity of vibrational bands and the optimized geometrical parameters of the compound are evaluated using HF and DFT (LSDA/B3LYP/B3PW91/MPW1PW91) methods with 6-311+G(d,p) basis set. The theoretical wave numbers are scaled down and compared with the experimental values which showed very good agreement. Comparison of stimulated spectra with the experimental spectra provides important information about the ability of the hybrid computational method to describe the vibrational modes. The HOMO, LUMO, chemical hardness ( η), chemical potential ( μ), electrophilicity values ( ω) and maximum amount of electronic charge transfer (Δ N max) are calculated. The molecular electrostatic potential (MESP) is calculated and the corresponding graphs are drawn. Some thermodynamic parameters and physico-chemical properties are calculated and discussed.