Electronic and vibrational spectroscopic studies of jet-cooled 5-cyanoindole and its water clusters, 5CI–(H2O)n, (n = 0–2)

Abstract

Mass-selected resonant two-photon ionization (R2PI) and UV–UV hole-burning, and infrared-dip spectra of 5-cyanoindole (5CI) and its water clusters, 5CI–(H2O)n (n=1 and 2) were measured. Although, the structures of 5CI–(H2O)1–2 are similar to those of 3CI–(H2O)1–2, the photofragmentation behaviors of the two systems are quite different due to the La–Lb state energy lowering and higher binding energies of 5CI–(H2O)1–2 compared to those of 3CI–(H2O)1–2. Especially for the case of 5CI–(H2O)2 cluster, shortening excited-state lifetime of 5CI–(H2O)2 causes the broad background in the R2PI spectrum of 5CI–(H2O)2.