Photodynamics of charge transfer and ion-pair states of Cl-2:Xe complexes in liquid Ar

Sequential two photon studies of Xe:Cl-2 complexes in liquid Ar are reported. The first photon prepares the excited state complex Xe:Cl-2((3) Pi(u)), which radiatively relaxes with a lifetime of 10+/-1 mu s (22+/-2 mu s for the uncomplexed Cl-2((3) Pi(u))). A second photon accesses either the molecular ion pair state, Xe:Cl+Cl-, or the contact charge transfer transition, Xe+Cl2-. The latter dissociates to Xe+Cl-+Cl even though the product is formed at threshold. The former undergoes charge rearrangement and decays radiatively via Xe+Cl2- ((2) Sigma(u))-->XeCl2((1) Sigma(g)). Analysis of the excitation and emission spectra of the key intermediate in laser induced harpoon reactions, Xe+Cl2-, leads to the conclusions that the complex is linear in both ionic and neutral states, and allows a direct contrast between dissociation dynamics on ionic versus neutral surfaces. (C) 1996 American Institute of Physics.