Sub-natural linewidth spectroscopy on core–valence doubly ionized states of OCS

Abstract

Core–valence doubly ionized states of OCS, which are produced by the Coster–Kronig transitions following the S 2s ionization, have been investigated by using threshold photoelectron-Auger electron coincidence spectroscopy. The sub-natural linewidth regime achieved with this coincidence method enables us to locate the core–valence OCS2+ states, while the corresponding structures are almost smeared out on the S 2s Auger spectrum measured with conventional Auger electron spectroscopy.

Ultrafast molecular dynamics of dissociative ionization in OCS probed by soft x-ray synchrotron radiation

“…At higher values of KER (27)(28)(29)(30)(31)(32) and 32+ eV) the concerted process shifts to the left until it is centered horizontally on the simulation, indicating a higher degree of simultaneity, consistent with the assumption of instantaneous bond breaking. This is the first such observation of a horizontal shift in the position of the concerted process but inspection of [50] shows the existence of an overall shift for the few cycle laser results which also exhibit overall lower peak in KER consistent with the trend observed here. A further significant feature, of the plots is the progressive restriction of the concerted region in the vertical direction, towards the equilibrium point, with increasing KER, which is consistent with both bonds breaking more rapidly.…”

“…Hikosaka et al [50] have studied the Sulfur (2s) Auger spectrum at sub natural linewidth resolution. This was done by exciting the OCS S(2s) photoelectron at threshold and measuring Auger threshold coincidences.…”

Multi-electron spectroscopy: Auger decays of the argon 2s hole

“…[22][23][24][25] The major improvement of these further studies was the development of strategies to increase electron-electron coincidence efficiency. These include time of flight (TOF) spectrometers [26][27][28] which enable simultaneous observation of a large electron energy range, new electrostatic analysers of a large acceptance angle, 29 simultaneous use of several electrostatic 30 or TOF analysers, [26][27][28]31,32 threshold electron analysers [33][34][35][36][37][38][39][40][41][42] which allow a 4p detection of low energy electrons (less than a few tenths of meV) and reaction microscopes which reconstruct photoelectron-Auger electron coincidences from ion recoil. 43,44 These photoelectron-Auger electron and Auger electron-Auger electron coincidences made it possible to study triply charged ions such as Ar 3+ , 27 Kr 3+28 and Xe 3+ .…”

“…28,35 They also revealed details of the spectra of dications and the dynamics of their formation in the Auger process, both in atoms 26,33,34,36,38,39,41 and in molecules. [30][31][32]37,40,[42][43][44] It was soon realized that photoelectron-Auger electron coincidences probe the resultant dicationic states directly, and that the inherent resolution limit of conventional Auger spectroscopy due to the finite lifetime of the core hole could be overcome. This property leads to the so called 'Subnatural Linewidth Auger-Photoelectron Coincidence Spectroscopy'.…”

Photoelectron–Auger electron coincidence spectroscopy of free molecules: New experiments

“…1). For a number of systems, Coster-Kronig decays from inner valence states have been investigated thus [16][17] [18]. In future detailed studies of the nuclear dynamics in the intermediate (core ionized) state may therefore become possible [19] [20].…”