Molecular Structure and TD-DFT Study of the Xylene Isomers

Abstract

In this work, we have investigated the xylene isomers in concepts of vertical and adiabaticionization energy parameters and molecular orbital (HOMO-1, HOMO/SOMO, LUMO,LUMO+1) energies of the neutrals and singly charged cation radicals. As a first step of thecalculations, conformational analysis has been performed for all isomers using the semi-empiricalmethod with PM3 core type Hamiltonian. Geometry optimization and frequency calculationswere performed by using Density Functional Theory (DFT) with Becke, three-parameter, LeeYang-Parr(B3LYP) exchange-correlation functional and 6-311++G(d,p) basis sets. UV-Viselectronic spectra of the neutral xylene isomers were calculated by using the TD-DFT methodwith cam-B3LYP functional and 6-311++G(2d,2p) basis set.