Understanding the Second-Order Nonlinear Optical Properties of One-Dimensional Ruthenium(II) Ammine Complexes

Abstract

First principles calculations of the linear and nonlinear optical properties are carried out for three series of one-dimensional ruthenium(II) ammine complexes with one pyridyl pyridinium ligand containing different numbers of C2H2 units or the (CH═CH)—Ph—(CH═CH) linker. The substitution effects upon introducing one pyridine or one N-methylimidazole moiety as donor instead of ammonia have also been studied in detail. These calculations employing density functional theory with different exchange-correlation functionals as well as the polarizable continuum model approach to describe the solvent effects show that these compounds are challenging for theoretical chemistry and that their nonlinear optical responses are complex and depend on many structural and electronic factors. Two major types of methods have been employed to calculate and analyze the first hyperpolarizabilities (β): (i) the summation-over-states scheme, applied to calculate the longitudinal β tensor component, truncated to one or two dominan...