Photodissociation dynamics of propargyl alcohol at 212 nm: the OH production channel.

Photodissociation dynamics of propargyl alcohol (HC identical withC-CH(2)OH) at 212 nm in the gas phase was investigated by measuring rotationally resolved laser-induced fluorescence spectra of OH ((2)Pi) radicals exclusively produced in the ground electronic state. From the spectra, internal energies of OH and translational energy releases to products were determined. The electronic transition at 212 nm responsible for the OH dissociation was assigned as the pi(C[triple bond]C) --> pi*(C[triple bond]C) transition by time-dependent density functional theory calculations. In addition, an energy barrier at the exit channel along the reaction coordinate on the excited electronic potential energy surface was identified by ab initio calculations. The observed energy partitioning among the fragments was successfully modeled by the so-called "barrier-impulsive model".