The interference effects induced by two-color excitation in the photodissociation of IBr

Abstract

We have investigated the interference effects in the two-color dissociation of IBr using fundamental (560 nm) and its second-harmonic (280 nm) light. We have performed one-dimensional photofragment translational spectroscopy in the presence of two-color excitation. In the strong-excitation regime for the fundamental light (∼ 1.3×10 10 W cm −2 ), the yield of the spin–orbit excited iodine atoms dissociated from IBr molecules shows an oscillating behavior that is dependent on the relative phase between the fundamental and the second-harmonic light. This phase-dependent behavior can be explained by the interference between a one-photon transition induced by the second-harmonic light and a dipole-forbidden two-photon transition induced by the strong fundamental light.