NONLINEAR-OPTICAL PROPERTIES OF TRANSITION METAL-PHOSPHINE COMPLEXES

Nonlinear optical properties of transition metal-phosphine complexes h ave been measured at 532 nm by degenerate four-wave mixing. Large nonr esonant second-order molecular hyperpolarizabilities, gamma, have been found for complexes containing two phosphine ligands. The measured ga mma values are closely related to the type and coordination geometry o f the phosphine ligands. A numerical fitting of gamma values versus th e number of substituents with pi-electrons on the ligand gives a resul t similar to what is observed for linear conjugated oligomers.