Theoretical Simulation of the Third Order Nonlinear Optical Properties of some Selected Organometallics Complexes

Organometallic complexes have been intensively studied for 15 years and they are still investigate due to their interesting physical and chemical properties [1]. The investigated organometallics composites possess transition metals Ru and Cr and that's why investigation of their properties is very interesting with regard on metastable trapping levels originated from the d-states. Our interest is also focused on thiophene-based spacers such as oligothiophenes of various lengths and dithienylethylene. In this work we will determine the influence of these molecular structures on the improvement of their third-order NLO properties exploiting in particular the nature of the acceptor fragment and the pi-conjugated transmitter. Third-order frequency-dependent molecular polarizability gamma of the organometallics has been calculated using the Sum-Over-State (SOS) method. The origin of the non-linear optical properties of the investigated molecules is discussed within the semi-empirical ZINDO/1 approximation in frame of Restricted Hartree-Fock approach [2]. Third order nonlinearities for the studied compounds were measured by degenerate four waves mixing (DFWM) experiment. The investigation of kinetics the third order nonlinear optical processes of organometallic embedded in polymethyl methacrylate (PMMA) and polyvinylcarbazole (PVK) polymer matrix will be introduced [3]. A comparison between theoretical results and experimental data will be presented.