Molecular supersonic jet studies of aniline solvation by helium and methane

The technique of two color resonant two photon ionization coupled with time of flight mass spectroscopy has been employed to study aniline–He (AnHex) and aniline–CH4 [An(CH4)x] van der Waals clusters generated in a supersonic molecular jet. This technique allows identification of spectroscopic transitions with clusters of known mass because no ion fragmentation is observed. Specific features in the optical fluorescence excitation and dispersed emission spectra can thereby be uniquely identified with a particular cluster. Cluster vibrations can be analyzed by a Morse potential to yield the An–He bond dissociation energy D0∼100±50 cm−1. Careful analysis of the dispersed emission from AnHex suggests 145