Dissociative Charge Exchange Dynamics of HOCO+ and DOCO+

Abstract

Translational spectroscopy has been used to study the dissociation of HOCO and DOCO to both the OH/OD(X(2)Pi) + CO(X(1)Sigma(+)) and H/D((2)S) + CO(2)(X(1)Sigma(+)) product channels upon charge exchange between a fast (keV) beam of HOCO(+)/DOCO(+) and cesium. Analysis of the measured kinetic energy release distributions for the two product channels suggests that HOCO is initially produced in the 1(2)A'' electronic state by near resonant electron capture from cesium (approximately 4.31 eV above the ground state trans-HOCO conformer). This initial state undergoes rapid predissociation leading to OH + CO and H + CO(2) products, with respective branching fractions of 0.75 +/- 0.03 and 0.25 +/- 0.03. Possible mechanisms leading to dissociation and the observed dissociation dynamics are presented in light of theoretical studies of the low-lying electronic states of HOCO.