ICN photodissociation at 193 nm; CN(B 2Σ) rotational distributions and fluorescence polarization

Abstract

The rotational distribution of CN(B 2Σ, v=0) dissociated from ICN at 193 nm is well represented by a thermal rotational distribution for T=250 K, giving an average energy of 175 cm −1. The energy of the highest rotational state detected ( N=28) suggests that some or all of the molecules dissociated have appreciable internal energy. We discuss recent values of the available energy. Polarization of the R(8) line of the CN(B) fluorescence agrees with other experiments in this absorption feature, and gives the same upper-state symmetry observed at shorter wavelengths. CN(A 2Π) was also detected promptly after the fragmentation.