Product vibrational state distributions in the photodissociation of iodine - rare gas clusters

The photodissocn. of I2M van der Waals clusters is studied at several wavelengths above the B state dissocn. limit with M = Ne, Ar, Kr, and Xe. The I2 product vibrational state distributions are obtained by measuring the dispersed B -> X fluorescence and analyzing the resulting spectra; excitation above the B state dissocn. limit leads to significantly different reaction dynamics compared to excitation of the bound levels of the B state studied previously. Among others the recoil energies of the I2 and M fragments are much larger, and the distributions of rovibrational states in the I2 product are much wider in the present expts. The relative translational energy in the I2* and M photodissocn. products is significantly larger than predicted by recent quasi-classical trajectory calcns. The fragment recoil energy does not vary strongly with the excitation wavelength.