Exploring the OH plus CO reaction coordinate via infrared spectroscopy of the OH-CO reactant complex

A hydrogen-bonded complex of OH with CO is identified along the reaction coordinate for the OH+CO <----> HOCO -->H+CO2 reaction. The existence of this linear OH-CO complex is established by infrared action spectroscopy, which accesses vibrational stretching and bending modes of the complex. Complementary electronic structure calculations characterize the OH-CO and OH-OC complexes, the transition state for HOCO formation, and the reaction pathways that connect these complexes directly to the HOCO intermediate. (C) 2000 American Institute of Physics. [S0021-9606(00)02246-7].