DFT STUDIES ON ELECTRONIC STRUCTURES AND THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF A SERIES OF Pt-Pt BOND-CONTAINING METAL COMPLEXES.

In this paper, electronic structures and third-order nonlinear optical (NLO) properties of a series of Pt-Pt bond-containing metal complexes have been calculated by using the density functional theory (DFT) combining with the sum-over-states (SOS) method. In order to check the reliability of this method, the electron correlations and basis sets have been compared. Our calculated results show that introduction of electron donor, thiophene ring and lengthing of organic conjugated ligand can enhance third-order NLO responses. The electronic structure analysis shows that the [Pt-Pt(H2P(CH2)PH2)2] fragment displays strong electron-withdrawing character in these systems. Meanwhile, the third-order NLO response of Pt-Pt bond also has been estimated by using TDDFT-SOS method. An enhancement of third-order NLO response has been observed because of the introduction of the Pt-Pt bond. This is mainly due to the intense and low-lying metal-to-ligand charge transfer (MLCT) and intraligand (IL) CT transitions. [ABSTRACT FROM AUTHOR]