Vibrational Spectral Analysis, HOMO-LUMO plot and Electrostatic Potential Surface Map of Dimethylisophthalate

The FT-IR and FT-Raman spectra of dimethylisophthalate have been recorded in the region 4000-400 cm-1 and 3500-100 cm-1 respectively. Optimized geometrical structure and harmonic vibrational frequencies have been computed by the B3LYP density functional levels using 6-31G (d, p) and 6-311++G (d, p) basis sets. The observed FT-IR and FT-Raman vibrational frequencies are analyzed. The geometries and normal modes of vibration obtained from DFT method are in good agreement with the experimental data. The charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, the molecular electrostatic potential have been were calculated and analyzed.