Knowledge Bank

First row transition metal ion-benzene complexes of the form $M+(benzene)1-3$ are produced by laser vaporization in a pulsed nozzle source, mass-selected in an ion-trap mass spectrometer and excited in the infrared with a free electron laser. Multiphoton dissociation occurs by the elimination of whole benzene molecules. The photofragment yield versus wavelength produces IR resonance-enhanced multiphoton photodissociation (IR-REMPD) spectra for these complexes. Vibrational bands observed in the $600-1800cm-1$ region correspond to modes in the benzene molecules, but are shifted from those of free benzene due to the interaction with the metal ion.