Observation of the infrared spectra of the NH2-stretching vibration modes of aniline-Ar-n (n=1,2) clusters in a supersonic jet using REMPI

The infrared spectra of the NH2 stretching modes of aniline-Ar-n (n = 1, 2) clusters and corresponding cluster cations in a supersonic jet have been observed using an IR-REMPI double resonance technique, The observed frequencies of the aniline-Ar cluster are nu(sym) = 3422, and nu(asym) = 3508 cm(-1), and those of the aniline-Ar+ cation are nu(sym) = 3395 and nu(asym) = 3489 cm(-1). The frequency shifts of the NH2 stretching modes due to the Ar atoms have been found to be small, The aniline-Ar+ cluster ionized by the REMPI method has been found to be cold and the infrared spectrum shows no hot bands from the van der Waals modes, even though the excess energy above the ionization is as much as 5600 cm(-1). A process which gives the cold clusters is discussed.