Multi-dimensional wave-packet dynamics in potoinduced phase transition materials

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<Transition metal complexes> We investigated time resolved luminescence in Pt-Br at low temperature. We have found that the luminescence intensity increases anomalously at the low energy end of the wave packet (WP) oscillation. When the main part of the WP turns back to the high energy end, some part goes opposite direction. By comparing the results with a model calculation, we concluded that the WP splits on the top of the adiabatic potential curve connecting the self-trapped-exciton (STE) and the soliton pair state.We investigated the time resolved luminescence of Pd-Br complexes. We found that the STE state does not exist in this material, in spite of the charge-density-wave (CDW) ground state. The WP propagates to the state lower than the band gap without oscillation. This reflects the WP dynamics representing the phase transformation from Peierls insulator to Mott insulator.<F-centers in alkali halides> We observed the WP dynamics in F-centers. We found an asymmetric spectrum and unequal decay dynamics at high and low energy sides of the luminescence peak. This seems to originate from the large anharmonicity due to anticrossing between the 2s and 2p states. This is a good example of the WP dynamics on the potential curve with a crossing, which will useful for understanding the dynamics of photoinduced phase transitions.<Bio-materials> We observed the untrafast luminescence in aqueous solution of cytochrome c for the first time and assigned a luminescence peak to Q band. The result indicates that the non-radiative transfer of the electron to the d-orbital of Fe ion occurs within 300 fs. A long lifetime component is found and assigned to the state with a dessociated methionine group. These results clarify the relaxation dynamics of cytochrome c, which has not been known due to low luminescence intensity.