Submicrosecond-to-microsecond transient absorption measurements shown in Fig. were conducted using a TSP-2000 time-resolved spectrophotometer (Unisoku). The third harmonics (355 nm) of a 10 Hz Q-switched Nd:YAG laser (~5 ns pulse, Minilite II, Amplitude Japan) were used as the excitation light and the laser pulse was irradiated to the sample placed in a 10-mm quartz cuvette without a defocusing lens under nitrogen atmosphere.