Projection of excited orbitals into kinetic energies of emitted electrons in resonant SiKLLAuger decays of SiF4

Abstract

Spectator resonant Auger-electron spectra have been measured in the Si 1s photoexcitation region of SiF 4 using an electron spectroscopic technique combined with undulator radiation. A transition with the highest intensity in the total ion yield spectrum, which comes from excitation of a 1s electron into the 6t 2 valence orbital, generates resonant Auger decays in which the excited electron remains predominantly in the valence orbital or is partly shaken up into a high-lying Rydberg orbital. The higher-lying peak generated through excitation into Rydberg orbitals induces resonant Auger decays in which the excited Rydberg electron is partly shaken up to a higher-lying Rydberg orbital or shaken down to a lower-lying valence molecular orbital. These findings exhibit a clear disentanglement effect among excited orbitals which are smeared out in the 1s electron excitation spectrum.

A variety of characteristic behaviour of resonant KL23L23Auger decays following Si K-shell photoexcitation of SiCl4

“…The term KE means the electron kinetic energy. This spectator transition has been found in SiF 4 and related molecules with the Si atom, as described previously [11][12][13].…”

“…The island around the electron kinetic energy of 1602 eV, V , is probably yielded by a shake-up transition of an excited electron. This type of process takes place in the KL 23 L 23 resonant Auger decay of some Si-containing molecules [11][12][13], and this is expressed with the following:…”

“…The analysed spectra provided energies of doubly charged molecular ions having two Si 2p holes and indicated that a state of 1 D 2 in the atomic representation had the dominant intensity [9]. Since simple spectra were measured for resonant KLL Auger transitions, an energy transformation of photoexcited states into electron kinetic energies was elucidated in spectator resonant KLL Auger electrons of SiF 4 and similar molecules [11][12][13]. On the other hand, post-collision interaction (PCI) takes place near the ionization threshold, which induces distortion of peak shapes of NA components and re-capture of a slow core photoelectron.…”

Theoretical spectroscopy on K–2, K–1L–1, and L–2 double core hole states of SiX4 (X=H, F, Cl, and CH3) molecules

“…It is worth noting here that DCH states of the L À2 type can be populated as final states of KLL Auger decay in any molecules including the third row atoms (see, e.g., [22][23][24][25][26][27]). For SiH 4 and SiF 4 , 2s À2 , 2s À1 2p À1 and 2p À2 DCH states were observed as finals states of the KL 1 L 1 , KL 1 L 23 and KL 23 L 23 Auger transitions, respectively [22,23].…”

Molecular cascade Auger decays following Si KL23L23Auger transitions in SiCl4

“…For a long time it was very difficult to produce an intense monochromatic photon beam in the energy region of excitation of Si 1s electrons. However, recent advances in the undulator beam line at SPring-8 and in highly sensitive electron spectrometers have enabled us to measure electron spectra at an appropriate resolution for electrons generated through photoexcitation of Si 1s electrons [23][24][25][26][27][28][29][30]. In resonant KLL Auger electron spectra of Si-containing molecules, Auger decays dominantly yield molecular ion states with a component of the 1 D 2 term of the Si atom, and the excited electron behaves as a spectator in these decays [23][24][25][26][27].…”