Core-Level Spectroscopy of 2-Thiouracil at the Sulfur L1- and L2,3-Edges Utilizing a SASE Free-Electron Laser
Fabiano Lever, Dennis Mayer, Jan Metje, S. Ališauskas, Francesca Calegari, S. Düsterer, R. Feifel, Mario Niebuhr, Bastian Manschwetus, Marion Kuhlmann, Tommaso Mazza, M. S. Robinson, Richard J. Squibb, Andrea Trabattoni, Måns Wallner, Thomas Wolf, Markus Gühr
Abstract
In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L1- and L2,3-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster–Kronig and Auger–Meitner emission at the L1- and L2,3-edges, respectively. We used the electron yield to construct X-ray absorption spectra at the two edges. The experimental data obtained are put in the context of the literature currently available on sulfur core-level and 2-thiouracil spectroscopy.