Photodissociation of HCN at 157 nm: Energy disposal in the CN(A 2Π) fragment

Abstract

Photodissociation of HCN at 157 nm was found to produce only H and CN(A 2Π) through analysis of laser-induced fluorescence experiments. The CN(A 2Π) vibrational populations decrease monotonically from v=0 to 3, represent 19±1% of the available energy and are in good agreement with a prior distribution of 9500 cm−1 of energy. The rotational distributions of the four vibrational levels are very similar, represent 6.5% of the available energy and are approximately Boltzmann with temperatures near 900 K. The rotational distribution of CN(A 2Π,v=0) is compared to several highly simplified reference distributions and approximate agreement is found with a phase space calculation.