First-principle study on polarizability and hyperpolarizability of a transition metal cluster,[Mo 2 S 3 (C 6 H 11 ) 3 (CO) 6 ]·N(C 2 H 3 ) 4

Abstract

We reported the first-principle study of linear and nonlinear optical polarizability of a di-nuclear transition metal cluster, [Mo₂S₃(CO)₆(C₆H₁₁)₃]·N(C₂H₃)₄, by using finite-field method. The calculations were performed at an HF/Lanl2dz level. The spatial average value of the first hyperpolarizability along z direction was very large, ${\mathit{\beta }}_{\mathit{z}}=13.8\times {10}^{-30}$ esu, indicating the potential applications of this cluster for IR nonlinear optical processes. Our results showed that the charge transfer inside the metal core cluster, [Mo₂S₃(CO)₆], played an important role in nonlinear optical response while the joint effect of metal core and organic ligands (C₆H₁₁)₃ also contributed to nonlinear optical polarizability. In addition, the organic ionic group, [N(C₂H₃)₄]⁺, situated in z direction enhanced the ${\mathit{\beta }}_{\mathit{z}}$ value. The study may help us to understand the nonlinear optical nature of the transition metal clusters and provided an example to show the computational efficiency of finite-field method in the first-principle theoretical study of the complex system containing transition-metal element.