Electronic spectroscopy of the OH–CO reactant complex

A broad and relatively unstructured electronic excitation spectrum has been observed for the OH–CO reactant complex in the OH A–X (1,0) region by laser-induced fluorescence and fluorescence depletion methods. The electronic spectrum spans from 33 500 to 36 050 cm−1 and peaks near 34 600 cm−1. Fluorescence depletion methods have been employed to demonstrate that the broad electronic spectrum originates from the same linear, hydrogen-bonded OH–CO complex that gives rise to a rotationally resolved infrared spectrum. The electronic spectrum is consistent with a Franck–Condon mapping of the ground state radial distribution on a strongly attractive excited state potential that undergoes rapid decay dynamics.