The photoelectron spectrum of HCl and DCl studied with ultraviolet excitation, high resolution x-ray excitation, and synchrotron radiation excitation: Isotope effects on line profiles

Abstract

The HCl and DCl molecules have been studied with monochromatized x-ray, ultraviolet, and synchrotron radiation excited photoelectron spectroscopy. Isotope effects are detected in the outer and inner valence bands using all the different excitation sources. These effects are used to describe the nature of the potential curves for the 5σ−1 state and various inner valence correlation states. The 5σ−1 state is shown to predissociate at 18.0 eV into Cl+(3P)+H(2S). The potential curves for the two outermost states in the 4σ−1 region are approximately determined. The outermost state is shown to be repulsive, whereas the second state, that corresponds mostly to the 4σ−1 single hole state, is found to be bound. One weak structure that must be associated with the 2∏ manifold of states is observed at 28.6 eV binding energy. Three structures at binding energies larger than 40 eV are reported for the first time.