Femtosecond Dissociation of Core-Excited HCl Monitored by Frequency Detuning

Abstract

Core excitation of gaseous HCl to the dissociative ${\ensuremath{\sigma}}^{*}$ state leads to a deexcitation spectrum with two qualitatively different contributions---a broad molecular background and narrow atomic lines. The experiment demonstrates that the ratio of integrated intensities from these two contributions depends crucially on the excitation frequency; the molecular background is enhanced with increased detuning of the photon frequency. This is discussed in a time-dependent model, using the concept of an effective duration time for the resonant x-ray scattering process.