Nonlinear optical (NLO) properties of novel organometallic complexes: high accuracy density functional theory (DFT) calculations

Abstract

Density Functional Theory (DFT) calculations are performed to determine the accurate first static hyperpolarizability ( β) of nitrogen bound low valent (M 0) group six metal carbonyls representing the class of chromophores displaying weak coupling between donor and acceptor. The nonlinear optical (NLO) response of this class of second-order NLO metal complexes is dominated by metal-to-ligand charge transfer excitations involving low lying, filled metal-carbonyl based orbitals and empty π ∗ orbitals of nitrogen bound ligand. We report novel organometallic systems with high β values. The full geometry optimizations of chromium and tungsten carbonyls were performed using DFT method at B3LYP/LanL2DZ level of theory using gaussian98W. The calculations of the first hyperpolarizability ( β) of these complexes were performed at the same level of theory. The calculated values of β were compared with available data in the literature. To understand the variation of β in these complexes, we examined the molecular HOMO and molecular LUMO generated via gaussian98W. The present study concludes that these organometallic systems may contribute to the development of NLO materials.