Solvent caging by diatomic molecules in the photodissociation of molecular iodine-diatomic molecule (I2M) clusters

The reaction I2M + hn -> I2(B) + M (M = H, N, O, I) was studied following excitation of the I2M cluster above its B state dissocn. limit. Dispersion of the I fluorescence allows for the detn. of the relative populations of a no. of the vibrational levels v' of the B state. The relative importance of the hindered dissocn. pathway appears to increase with decreasing photon energy as compared to the alternative (unobserved) path in which the I-I bond is broken, and the photofragment recoil energy tends to increase with increasing mass of M. An exceptionally large wavelength dependence of the I2(B) yield for the dissocn. of I2O2 was obsd.