Alternative Pathway to Double-Core-Hole States
Iyas Ismail, Anthony Ferté, F. Penent, R. Guillemin, Dawei Peng, T. Marchenko, Oksana Travnikova, Ludger Inhester, Richard Taïeb, Abhishek Verma, Nicolas Velasquez, Edwin Kukk, Florian Trinter, Dimitris Koulentianos, Tommaso Mazza, T. Baumann, Daniel E. Rivas, Yevheniy Ovcharenko, Rebecca Boll, Simon Dold, A. De Fanis, Markus Ilchen, Michael Meyer, Gildas Goldsztejn, Kai Ming Li, Gilles Doumy, Linda Young, G. Sansone, R. Dörner, M. N. Piancaśtelli, S. Carniato, John D. Bozek, R. Püttner, M. Simon
Abstract
Excited double-core-hole states of isolated water molecules resulting from the sequential absorption of two x-ray photons have been investigated. These states are formed through an alternative pathway, where the initial step of core ionization is accompanied by the shake-up of a valence electron, leading to the same final states as in the core-ionization followed by core-excitation pathway. The capability of the x-ray free-electron laser to deliver very intense, very short, and tunable light pulses is fully exploited to identify the two different pathways.