Spectral sharpening of the Pt L edges by high-resolution x-ray emission

Abstract

The platinum 2p(3/2), 2p(1/2), and 2s x-ray absorption spectra, recorded by monitoring the fluorescence intensity with eV energy resolution, show a spectral broadening that is significantly less than the 2p and 2s core hole lifetime broadening. The background of such spectral sharpening is discussed. It is shown, experimentally as well as theoretically, that the lifetime broadening of the 2p and 2s core holes is replaced by a new lifetime broadening. It is demonstrated that from the combination of normal x-ray absorption, selective x-ray absorption, and x-ray emission, the individual lifetimes of all participating core states can be determined. The difference between the 5d(5/2) and 5d(3/2) densities of states can be obtained from a combination of the 2p(1/2) and 2p(3/2) x-ray absorption spectra. The present spectra are limited by the experimental resolution. With the prospect of an improved experimental resolution for x-ray excitation and decay, the Pt edge absorption spectra could be obtained with even better resolution, thus providing a high-resolution hard x-ray probe of the empty density of states with important advantages for in-situ and high-pressure studies.