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| 2. |
- Kivimäki, A, et al.
(författare)
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Resonant Auger spectroscopy of argon clusters at the 2p threshold
- 2005
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 71:3
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Tidskriftsartikel (refereegranskat)abstract
- Resonant Auger spectra of large argon clusters have been measured at the Ar 2p edge. The decay spectra can give some information on the states reached in photon absorption. For example, the observation of the 3p(4)4p final states indicates the occurrence of the 2p(3/2)-> 4p excitation in clusters, whereas in atoms this excitation is dipole forbidden. Also the 3p(4)3d final states are identified in the resonant Auger spectra. A peculiar finding is that the normal Auger transitions in bulk cluster atoms are observed below the 2p ionization thresholds. This is explained by the excitation of the 2p electrons into the conduction band, followed by a rapid delocalization of the electron.
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| 4. |
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| 5. |
- Tchaplyguine, Maxim, et al.
(författare)
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Magnetron-based source of neutral metal vapors for photoelectron spectroscopy
- 2006
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 77:3
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Tidskriftsartikel (refereegranskat)abstract
- The construction of a magnetron-based source for neutral metal vapors is presented. The first photoelectron spectroscopy experiments with the source using synchrotron radiation at MAX-lab, Sweden are described. Photoelectron spectra of atomic copper, silver, and nickel are reported with an 80 meV resolution for Cu and Ag, previously not achieved in experiments using synchrotron light. (c) 2006 American Institute of Physics.
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| 7. |
- Abu-samha, M, et al.
(författare)
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Lineshapes in carbon 1s photoelectron spectra of methanol clusters
- 2006
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084. ; 8:21, s. 2473-2482
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Tidskriftsartikel (refereegranskat)abstract
- A general protocol for theoretical modeling of inner-shell photoelectron spectra of molecular clusters is presented and applied to C1s spectra of oligomers and medium-sized clusters of methanol. The protocol employs molecular dynamics for obtaining cluster geometries and a polarizable force field for computing site-specific chemical shifts in ionization energy and linewidth. Comparisons to spectra computed from first-principle theories are used to establish the accuracy of the proposed force field approach. The model is used to analyze the C1s photoelectron spectrum of medium-sized clusters in terms of surface and bulk contributions. By treating the surface-to-bulk ratio as an adjustable parameter, satisfactory fits are obtained to experimental C1s spectra of a beam of methanol clusters.
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| 8. |
- Bergersen, Henrik, et al.
(författare)
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First observation of vibrations in core-level photoelectron spectra of free neutral molecular clusters
- 2006
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 429:1-3, s. 109-113
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Tidskriftsartikel (refereegranskat)abstract
- Core-level photoelectron spectra of free neutral methane clusters have been recorded. These spectra exhibit well-resolved surface and bulk features as well as vibrational fine structure. The vibrational structure in the cluster signal is well reproduced by a theoretical model that assumes independent contributions from inter- and intramolecular modes. The intramolecular contribution to the vibrational line-shape is taken to be equal to that of the monomer in the gas phase, while the intermolecular part is simplified to line broadening. An estimate of the cluster size has been made on the basis of the observed surface-to-bulk intensity ratio.
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| 9. |
- Bergersen, Henrik, et al.
(författare)
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Two size regimes of methanol clusters produced by adiabatic expansion
- 2006
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 125:18, s. 184303-
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Tidskriftsartikel (refereegranskat)abstract
- Free neutral methanol clusters produced by adiabatic expansion have been studied by photoelectron spectroscopy and line shape modeling. The results show that clusters belonging to two distinct size regimes can be produced by changing the expansion conditions. While the larger size regime can be well described by line shapes calculated for clusters consisting of hundreds of molecules, the smaller size regime corresponds to methanol oligomers, predominantly of cyclic structure. There is little contribution from dimers to the spectra.
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| 10. |
- Gisselbrecht, Mathieu, et al.
(författare)
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Photon energy dependence of fragmentation of small argon clusters
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 123:19
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Tidskriftsartikel (refereegranskat)abstract
- Photofragmentation of small argon clusters with size below ten atoms is reported. In this size range significant modifications from the electronic properties and geometry take place. When tuning the photon energy through the argon 2p edge, the fragmentation pattern is changed. Specifically, cation dimer production is enhanced at the 2p(3/2)-> 4s resonance, while above the 2p edge almost complete atomization is observed. In both cases, the widths of the peaks in the mass spectra indicate that a large amount of kinetic energy is imparted to the fragment due to the formation of multiply charged clusters. A model based on "Coulomb explosion"-charge separation, simply resulting in a complete atomization of the cluster with no dependence on the photon energy-is insufficient to explain the observed photofragmentation of small clusters.
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