Photodissociation of ICN at the water/chloroform interface.

The photodissociation of ICN adsorbed at the water/chloroform liquid-liquid interface is studied using semiclassical molecular dynamics with nonadiabatic surface hopping. Several fundamental processes following the bond breakup of ICN adsorbed at the interface are compared with the same processes taking place in bulk water and bulk chloroform. These include cage escape, rotational relaxation of the CN product, recombination on the ground state to form ICN and INC, and their vibrational relaxation. The probability for cage escape at the liquid/liquid interface is larger than in the bulk of either liquid. Nonadiabatic transitions among the different electronic states have rates that are very similar in bulk water and at the interface but slightly more rapid in chloroform. The translational and rotational relaxation of the photofragments strongly depend on the final photodissociation outcome, but typically the dynamics in bulk water are slightly faster than at the water/chloroform interface and typically much faster than the behavior in bulk chloroform. The vibrational excitation of the ICN and INC products relaxes much slower in bulk chloroform than in bulk water, with the interface results falling in between, closer to the bulk water dynamics.