Excited-State Reaction Dynamics of the Radical Anions Revealed by the Novel Time-Resolved Photofragment Depletion Spectroscopy

Excited-state reaction dynamics of the radical anions have been investigated by a newly-developed time-resolved photofragment depletion (TRPD) spectroscopy where the different photodetachment cross-sections of the various anionic species during the reaction process were utilized to unravel their overall temporal evolutions. The otherwise formidable interrogation of the excited-state reaction dynamics of the radical anions, primarily due to the fact that their excited-states are often located above the electron detachment threshold, could be realized here. The shape of the excited-state potential energy surface of I2- has been clearly manifested in the TRPD transients taken at several different probe wavelengths, whereas the ultrafast internal conversion from the optically-excited nonvalence-bound state into the ground or excited valence-bound states of CH3NO2- or (CH3NO2)2-, which is followed by the fast chemical bond dissociation or the rather slow cluster decomposition, has been experimentally investigated for the first time to uncover the overall mechanism of the electron transfer dynamics among different (non)valence orbitals.