Journal of Chemical Physics, Vol.111, No.3, 923-930, 1999
The photodissociation of carbonyl cyanide CO(CN)(2) at 193 nm studied by photofragment translational energy spectroscopy
The photodissociation of carbonyl cyanide CO(CN)(2) at 193 nm was investigated by photofragment translational energy spectroscopy. For all the fragments created (CO, CN, OCCN, NCCN), the kinetic energy distributions were measured and two decay channels identified. The radical decay, CO(CN)(2)+h nu-->OCCN+CN, dominates with a yield of 94%+/-2% and shows the available energy mainly (82%) channeled into the internal degrees of freedom of the fragments. A fraction of 18%+/-6% of the nascent OCCN radicals has sufficient energy to spontaneously decay to CO+CN involving a barrier less than or equal to 160 kJ/mol. With a yield of 6%+/-2% the molecular decay produces the fragments CO+NCCN. These fragments acquire a high available energy owing to the formation of the new C-C bond in NCCN. An average fraction of 70% is partitioned into internal fragment energy. Even the fastest fragments are still internally hot, indicating that with the high barrier expected, a substantial exit channel interaction is operative. The isotropic recoil distribution found for the products CN, OCCN, and NCCN further suggests that both the radical and the molecular decay are, on the time scale of a parent rotation, slow and probably indirect.