Knowledge Bank

First row transition metal ion-benzene complexes of the form $M+$(benzene) $x$ and $M+$(benzene) $x$ Ar are produced by laser vaporization in a pulsed nozzle source, mass-selected in a time of flight mass spectrometer and excited in the infrared with an OPO/OPA laser system. Multiphoton dissociation occurs by the elimination of whole benzene molecules or argon. The photofragment yield versus wavelength produces IR resonance-enhanced multiphoton photodissociation (IR-REMPD) spectra for these complexes. Vibrational bands observed in the $2700-3300cm-1$ region correspond to vibrational modes in the benzene molecules but are shifted from those of free benzene due to the interaction with the metal ion.