STUDY OF HCO2 AND DCO2 BY NEGATIVE-ION PHOTOELECTRON-SPECTROSCOPY

Photoelectron spectra of HCO2- and DCO2- at 299 nm, 266 nm, and 213 nm are reported. Photodetachment accesses the (2)A(1), B-2(2), and (2)A(2) states of the formlyoxyl radical, HCO2. The (2)A(1) state is assigned as the HCO2 ground state, although it is nearly degenerate with the B-2(2) State (T-0=0.027 eV), and the (2)A(2) State lies at T-0=0.536 eV. The electron affinity of HCO2 is 3.498+/-0.015 eV. The spectra show partially resolved vibrational features, primarily involving progressions in the CO2 bending mode. The irregular appearance of the spectra in some regions suggests vibronic coupling between the (2)A(1) and (2)A(2) states. The possible role of the HCO2 radical as an intermediate in the OH+CO-->H+CO2 reaction and in H+CO2 inelastic scattering is discussed. (C) 1995 American Institute of Physics.