Vibrational predissociation of aniline-Inert gas cluster cations

Abstract

The molecular structures and predissociation dynamics of aniline (Phenylamine, PhNH2)-inert gas cluster cations PhNH2X+. (X = Ne, Ar, and Kr) were investigated by infrared (IR) spectroscopy coupled with density functional theory (DFT) calculations and IR photofragmentation studies. The ring isomer was the minimum energy structure for PhNH2Ne+ and PhNH2Ar+ whereas the N-H isomer was more stable in PhNH2Kr+. The decay constants of PhNH2X+ for ejection of X excited with IR depended strongly on the structure of PhNH2X+, presumably because the rate of intramolecular vibrational energy redistribution (IVR) was governed by the structure. As a result, the dissociation was faster for the larger PhNH2X+ clusters, because the rate of IVR was faster for the N-H type structure than the ring type. The decay constants deviate from those expected from the Rice-Ramsperger-Kassel-Marcus (RRKM) theory calculation by the factors of 10(4) or larger, manifesting that the dissociation occurred mainly via nonstatistical pathways. (C) 2016 Published by Elsevier B.V.