The spectroscopic (FT-IR, FT-Raman), MESP, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 1,5-dimethyl napthalene by density functional method

NBO study reveals that the lone pair orbital participates in electron donation to stabilize the molecule. Natural bond orbital analysis of the molecule confirms that the intramolecular charge transfer caused by π-electron cloud movement from donor to acceptor must be responsible for the non-linear optical properties of the title compound. Decrease in HOMO and LUMO energy gap, explains the eventual charge transfer within the molecule which is responsible for the chemical reactivity of the molecule. Some electron donor orbital, acceptor orbital and the interacting stabilization energy resulting from the second-order micro disturbance theory reported. Especially organic molecules are studied because of their larger NLO susceptibilities arising from β-electron cloud movement from donor to acceptor, fast NLO response times, high laser damage thresholds and low dielectric constants. The highest energy occupied molecular orbital (HOMO) of one molecule. The lowest energy unoccupied molecular orbital (LUMO) of the other molecule. The molecular electrostatic potential (MESP) is widely used as a reactivity map displaying the most probable regions for the electrophilic attack of charged point-like reagents on organic molecules.