Time- and frequency-resolved photoionisation of the allyl radical

We report picosecond time-resolved pump-probe photoelectron spectra of the allyl radical, C3H5, and the fully deuterated allyl, C3D5, carried out in o rder to elucidate the primary photophysical processes upon UV excitation. I t is shown that the UV bands of allyl decay in a two-step process: the firs t step is an internal conversion to the lower-lying A-state within 20 ps or less, while the second step is a very fast decay from the A-state to the e lectronic ground state through a conical intersection. In addition we repor t the first zero kinetic energy (ZEKE) photoelectron spectrum of allyl, yie lding an ionisation energy of 65762 cm(-1).