Molecular cascade Auger decays following Si KL₂₃L₂₃Auger transitions in SiCl₄

Abstract

Cascade Si LVV Auger electron spectra at the photoexcitation of the Si 1s electron in a SiCl4 molecule have been measured using an electron spectrometer combined with monochromatized undulator radiation. In the instance of the resonant excitation of the Si 1s electron into the vacant molecular orbital a peak with high yield is observed at about 106 eV, an energy considerably higher than the energies of the normal LVV Auger electron. This peak is presumed to originate from the participator decay from the state with two 2p holes and one excited electron into the state with one 2p hole and one valence hole. Following the normal KL23L23 Auger transition, the cascade spectrum shows several peak structures, e.g. 63 eV, 76 eV and 91 eV. The peak at 91 eV is probably assigned to the second step Auger decay into states having a 2p hole together with two valence holes. These findings are similar to experimental results of SiF4. The former two peaks (63 eV and 76 eV) are ascribed to Auger transitions of Si atomic ions produced through molecular ion dissociation after the first step cascade decays, although the peak heights of atomic ions are lower than those of SiF4.

Site-Specific Electron-Relaxation Caused by Si:2p Core-Level Photoionization: Comparison between F3SiCH2CH2Si(CH3)3 and Cl3SiCH2CH2Si(CH3)3 Vapors by Means of Photoelectron Auger Electron Coincidence Spectroscopy

“…The summation of the computational Si­[X]:L 23 VV and Si­[Me]:L 23 VV Auger electron spectra (AES) in each molecule is given in Figures a and a. For comparison, Figures and also represent Si:L 23 VV AES of Si­(CH 3 ) 4 , SiF 4 , and SiCl 4 vapors obtained previously. − The computational spectra of FSMSE and CSMSE given in Figures and are fairly consistent with the experimental spectra. The spectra of FSMSE vapor (Figure a–c) are similar to those obtained for condensed F 3 SiCD 2 CH 2 Si­(CH 3 ) 3 …”

“…Those peak groups could be assigned to Auger final states with two inner valence holes located on different Si−F bonds and to those with two inner holes confined on the same Si−F bond. 4c) is similar to the Si:L 23 VV AES of SiCl 4 (Figure 4e), 22,32 we have assigned the Si[Cl]:L 23 VV Auger peaks of CSMSE according to the result of our ab initio MO calculation for SiCl 4 (Supporting Information). Note that the hole-localization phenomena seen in SiF 4 were also reported in SiCl 4 .…”

“…Because the Si­[Cl]:L 23 VV AES of CSMSE (Figure c) is similar to the Si:L 23 VV AES of SiCl 4 (Figure e), , we have assigned the Si­[Cl]:L 23 VV Auger peaks of CSMSE according to the result of our ab initio MO calculation for SiCl 4 (Supporting Information). Note that the hole-localization phenomena seen in SiF 4 were also reported in SiCl 4 .…”

“…In Figures and , the Si­[Me]:L 23 VV AES of FSMSE and CSMSE are close to each other, and similar to that of Si­(CH 3 ) 4 vapor. , However, the Si­[X]:L 23 VV AES of FSMSE and CSMSE are totally different from each other. Furthermore, those are similar to the Si:L 23 VV AES of SiF 4 and SiCl 4 vapors, ,,, as mentioned in sections and . These observations of the Si­[XR]:L 23 VV AES of FSMSE and CSMSE (XR = F, Cl, or Me) would also show that the site specificity is maintained up to the Auger electron emission even in CSMSE.…”