Study of HCO2 and DCO2 by negative ion photoelectron spectroscopy

Abstract

Photoelectron spectra of HCO−2 and DCO−2 at 299 nm, 266 nm, and 213 nm are reported. Photodetachment accesses the 2A1, 2B2, and 2A2 states of the formlyoxyl radical, HCO2. The 2A1 state is assigned as the HCO2 ground state, although it is nearly degenerate with the 2B2 state (T0=0.027 eV), and the 2A2 state lies at T0=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 2A1 and 2B2 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.