Femtosecond fragmentation of CS2 after sulfur 1s ionization : interplay between Auger cascade decay, charge delocalization, and nuclear motion

Agradecimentos: The authors would like to thank the LNLS staff for technical support. This work received financial support from FAPESP (the Sao Paulo Research Foundation, Process number 2017/11986-5) and Shell and the strategic importance of the support given by ANP (Brazil's National Oil, Natural Gas and Biofuels Agency) through the R\&D levy regulation, National Council for Scientific and Technological Development, CNPq (401581/2016-0), the Swedish-Brazilian collaboration STINT-CAPES (9805/2014-01) and the Swedish Research Council VR (Grant 2017-04162). We acknowledge SNIC for allocated computing time on NSC and Uppmax. CC acknowledges the Helmholtz Association through the CFEL at DESY, the Swedish Research Council (VR Grant No. 2018-05973) Abstract: We present a combined experimental and theoretical study of the fragmentation of molecular CS2 after sulfur 1s Auger cascade decay, consisting of electron-multi-ion coincidence spectra of charged fragments and theoretical simulations combining density functional theory and molecular dynamics. On the experimental side, a procedure for a complete determination of all sets of ions formed is described. For many of the fragmentation channels, we observed a higher charge in one of the sulfur atoms than the other atoms. Based on these observations and the theoretical simulations where the time scale of the nuclear motion and decay is taken into account, we propose that KLL Auger decay after the 1s core hole creation, via 2p double hole states, results in highly charged and strongly repulsive states with one localized core hole. These localized core holes are sufficiently long-lived that some will decay after fragmentation of the molecular ion, thereby efficiently impeding charge exchange between the fragments FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado