We present high resolution zero kinetic energy photoelectron spectra of the
allyl radical through various intermediate vibronic states. The spectra yi
eld an ionization energy of 65 762 cm(-1), corresponding to 8.153 eV, as we
ll as frequencies for a number of cationic vibrational states. The spectrum
from the B 0(0)(0) state shows activity in modes corresponding to out-of-p
lane motion of the terminal -CH2 groups. This confirms the nonplanar geomet
ry of this state suggested previously, and thus provides additional insight
into the vibronic couplings in the intermediate states. (C) 2000 American
Institute of Physics. [S0021-9606(00)02326-6].