The dissociation of fluorobenzene Ar-n (n = 1-3) complexes was investigated using mass analyzed threshold ionization spectroscopy. All ion state spectra of the cationic complexes exhibit low-frequency vibrational progressions of van der Waals bending modes, which indicate a significant structural change of the complexes upon ionization. Upper limits for the dissociation thresholds in the cationic state could be determined for all complexes. In the case of fluorobenzene Ar-2 and fluorobenzene Ar-3, two fragmentation thresholds could be observed. (C) 1997 American Institute of Physics.