CN(B 2Σ +) photofragment fluorescence following two-photon excitation of ICN with a KrF laser

Abstract

Two-photon excitation of ICN with a KrF laser (248 nm) is shown to give rise to CN(B 2Σ +) photofragment fluorescence. The vibrational distribution in the CN(B 2Σ +) state is characterized by a temperature T v of 3200 ± 400 K. This is cooler than expected from previous work employing single-photon vacuum UV excitation. Possible reasons for this are discussed and it is suggested that two-photon excitation could populate different electronic states of ICN than those populated by a single-photon excitation. The role of the repulsive à state of ICN in the two-photon excitation process is also considered.