Study of molecular structure, polarizability, hyperpolarizability and HOMO-LUMO analysis of monomeric and dimeric structures of N-(3-methylphenyl)-2-nitrobenzenesulfonamide C13H12N2O4S

摘要

Density functional theory (DFT) calculations have been performed to obtain optimized geometries, highest occupied molecular orbital (HOMO) -lowest unoccupied molecular orbital (LUMO) energies, nonlinear optical (NLO), and thermodynamic properties for N-(3-methylphenyl)-2-nitrobenzene-sulfonamide of formula C13H12N2O4S in different solvents. B3LYP level gives similar results for geometric parameters. The most stable structure, which is defined by the highest energy gap between HOMO and LUMO, is obtained in gas phase (Delta E = 3.815888 eV), Obtained small energy gaps between HOMO and LUMO demonstrate the high-charge mobility in the titled compound. The magnitude of first static hyperpolarizability (beta) parameter increases by the decreasing HOMO-LUMO energy gap. The intensive interactions between bonding and antibonding orbitals of titled compound are responsible for movement of pi-electron cloud from donor to acceptor, that is, intramolecular charge transfer, inducing the nonlinear optical properties. So, the beta parameter for title compound is found to be in the range of 5.10598-9.03063 x 10(-30) esu, indicating the considerable NLO character. All of these calculations have been performed in gas phase as well as water and ethanol solvents in order to demonstrate solvent effect on molecular structure, vibration frequencies, NLO properties, etc.