THRESHOLD PHOTOELECTRON-SPECTRUM OF HOBR

The threshold photoelectron spectrum (TPES) of HOBr has been obtained in the wavelength regions corresponding to the first and second ionization bands. The adiabatic ionization potential (IP) is 10.642±0.005 eV; the O-Br stretching frequency in this X 2A″ state is found to be 730±20 cm-1. The adiabatic IP for the first excited state (A 2A′) of HOBr+ is 11.448 ± 0.005 eV. The latter value confirms an earlier, tentative conclusion based on the interpretation of autoionizing structure in the photoionization mass spectrum (PIMS). There is a slight difference in the TPES and PIMS values of the first adiabatic IP, whose origin is still somewhat ambiguous. © 1994 American Institute of Physics.