Molecular modelling, spectroscopic characterization and nonlinear optical analysis on N-Acetyl-DL-methionine

Abstract

In this present methodical study, besed on the density functional theory (DFT), the first-principles calculations have been employed successfully to study the structural and electronic properties of N-acetyl-DL-methionine (C7H13NO3S) which is a derivative of DL-methionine which is also known as DL-2-amino-4-methyl-thiobutanoic acid. Optimized molecular structure, vibrational frequencies, and also C-13 and H-1 NMR chemical shift values of the title compound are provided in a detailed manner by using B3LYP and HSEH1PBE functionals by applying 6-311++G(d,p) basis set for calculations using Gaussian 09W program. The comparison of the calculated values with the experimental values provides important information about the title compound. Besides the electronic properties (UV-Vis calculations) of the title compound, such as HOMO-LUMO energy values and energy gap, absorption wavelengths, oscillator strengths, were performed basing on the optimized structure in the gas phase. Moreover, the molecular electrostatic potential surface, dipole moment, nonlinear optical properties, linear polarizabilities, and first hyperpolarizabilities and chemical parameters have also been studied.