CO product distribution from metastable levels of HCO X̃ ²A′ prepared by stimulated emission pumping

Vibrational and rotational distributions have been measured for the CO produced following dissociation of HCO prepared in metastable ground-state levels by stimulated emission pumping. The metastable levels are characterized by high vibrational excitation in the HC-O stretching coordinate. The CO (v=2) rotational distribution following dumping of population on the ^QR₀(5) transition to the (0, 7, 0) level is rotationally cold and its distribution is in very good agreement with the theoretical prediction by Dixon. The linewidths for stimulated emission pumping transitions to the (0, 7, 0) and (0, 8, 0) levels are 1.0 and 1.6 cm^-1, respectively. Since it is possible to prepare a wide variety of metastable HCO levels whose wave functions sample different regions of the HCO potential energy surface, measurement of the dissociation dynamics of HCO so prepared should provide a detailed picture of the potential surface at energies from 0-10 000 cm^-1 above the dissociation limit.