| 1. |
- Partanen, L., et al.
(författare)
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2s photoionization and subsequent Auger cascade in atomic Si
- 2010
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 81:6
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Tidskriftsartikel (refereegranskat)abstract
- The 2s photoionization and subsequent Auger transition cascade in atomic Si were studied by means of synchrotron-radiation-induced electron spectroscopy. After the 2s photoionization, the core hole states decay predominantly by a two-step Auger transition cascade into the triply ionized [Ne]nl states. The ionization channels of the 2s core-ionized Si+ atoms to Si3+ ions were observed by measuring the conventional Auger electron spectra of the L-1-L2,3M Coster-Kronig transitions and the L2,3M-MMM Auger transitions. The observed L-1-L2,3M and L2,3M-MMM Auger spectra were analyzed by means of extensive multiconfiguration Dirac-Fock computations. We found that the electron correlation plays a prominent role in the Auger cascade, especially for the final-step Auger L2,3M-MMM spectrum. Additionally, it was seen that the L2,3M-MMM Auger spectrum of Si includes more Auger groups than the isoelectronic L-2,L-3-MMAuger spectrum of Al. Thus, more information on the intermediate ionic states is obtained if they are produced by Auger cascade rather than by direct photoionization.
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| 2. |
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| 3. |
- Osmekhin, S., et al.
(författare)
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Size-dependent transformation of energy structure in free tin clusters studied by photoelectron spectroscopy
- 2010
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 81:2, s. 023203-
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Tidskriftsartikel (refereegranskat)abstract
- Free nanoscale tin clusters in the average size range of a few tens up to similar to 500 atoms are studied by means of valence and core-level photoelectron spectroscopy. A self-consistent picture arises from comparison of the work functions derived from the 4d core-level spectra, the experimental ionization energies extracted from the 5p valence spectra, and the expectations from the metallic sphere model for the clusters. The present studies demonstrate that the 4d core-level energy changes are a sensitive probe of the metal-to-semiconductor transition in the size range under investigation.
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| 4. |
- Tchaplyguine, Maxim, et al.
(författare)
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Size-dependent evolution of electronic structure in neutral Pb clusters-As seen by synchrotron-based X-ray photoelectron spectroscopy
- 2014
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 195, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- Neutral Pb clusters in the size range from a few tens of atoms up to similar to 100 atoms are studied using synchrotron-based photoelectron spectroscopy. The electronic structure is seen to differ increasingly from that of the solid when the cluster size decreases. The valence band narrows gradually - down to about one fifth of the solid-state band width at the smallest size of few tens of atoms. Simultaneously the Fermi-edge energy shifts further away from the solid value by more than 2 eV. The Pb 5d core level binding energy also increases and the spectral features broaden and change in shape. The changes observed for the valence and for the 5d response energies and shapes are discussed in the context of the metal-to-insulator transition observed earlier in Pb clusters below the critical size of 20-30 atoms/cluster. (C) 2014 Elsevier B.V. All rights reserved.
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