| 1. |
- Jankala, K., et al.
(författare)
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Photon Energy Dependent Valence Band Response of Metallic Nanoparticles
- 2011
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 107:18
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Tidskriftsartikel (refereegranskat)abstract
- We show that the valence band response to photon impact in metallic nanoparticles is highly energy dependent. This is seen as drastic variations of cross sections in valence photoionization of free and initially charge-neutral nanosized metal clusters. The effect is demonstrated in a combined experimental and theoretical study of Rb clusters. The experimental findings are interpreted theoretically using a jellium model and superatom description. The variations are attributed to the changing overlap with the photon energy between the wave functions of diffuse delocalized valence electrons and continuum electrons producing a series of minima in the cross section.
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| 2. |
- Mikkela, M-H, et al.
(författare)
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Photoelectron spectroscopy of unsupported bismuth clusters: Size related effects of metallic properties
- 2012
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 112:8
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Tidskriftsartikel (refereegranskat)abstract
- Evolution of metallic properties of free and initially neutral nanoscale Bi clusters has been studied using synchrotron radiation excited photoelectron spectroscopy. The 4f and 5d core as well as the valence levels have been probed. The cross-level analysis indicates metallic properties in Bi clusters in the observed size range from 0.5 nm to 1.4 nm. The behavior of the core-level and valence binding energies as a function of cluster size has been observed to be smooth and relatively consistent. Valence responses for the largest clusters have their shape and width similar to those of the polycrystalline solid Bi. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759324]
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| 3. |
- Mikkela, M. -H., et al.
(författare)
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Size-dependent study of Rb and K clusters using core and valence level photoelectron spectroscopy
- 2011
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 64:2-3, s. 347-352
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Tidskriftsartikel (refereegranskat)abstract
- Electronic structure of free and neutral Rb and K clusters containing from few tens to few hundred atoms has been studied using synchrotron radiation. Core-level photoelectron spectroscopy has been used to probe the metallic nature of Rb and K clusters. We show that the metallicity exists down to the dimensions of few nanometers. Simultaneously the emergence and evolution of the valence band structure has been monitored by the valence-level photoelectron spectroscopy.
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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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| 5. |
- Urpelainen, Samuli, et al.
(författare)
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Size evolution of electronic properties in free antimony nanoclusters
- 2013
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 87:3, s. 035411-
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of electronic properties in free antimony (Sb) nanoclusters as a function of the cluster size has been studied experimentally using synchrotron radiation. Antimony 4d core-level and valence-band regions have been probed, and the 4d binding energies and valence ionization potentials of clusters of various mean sizes have been determined. The binding-energy shifts with respect to polycrystalline solid have been used for deriving the electronic properties of the clusters. The observed results suggest that even large Sb clusters are not metallic.
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