Dynamical process of photoinduced phase transition in a mixed-valence gold complex

The dynamical process of photoinduced phase transition from the mixed-valence (MV) state to a single-valence (SV) state has been investigated in a gold complex Cs2Au2Br6 by means of high-pressure Raman spectroscopy. We have found that the MV fraction decreases with excitation shot number, which is well reproduced by a contracted-exponential function. Such a characteristic dynamical behavior has been interpreted in terms of the stochastic formation of the photo-generated SV clusters and subsequent growth of the size.