| 1. |
- Qvarford, M., et al.
(författare)
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Polarisation-dependent X-ray absorption in high- and low-Tc Bi2Sr2Can-1CunO4+2n superconductors
- 1993
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Ingår i: Physica C: Superconductivity and its Applications. - : Elsevier BV. - 0921-4534. ; 214:1-2, s. 119-126
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Tidskriftsartikel (refereegranskat)abstract
- Taking advantage of the linear polarisation of synchrotron radiation, the polarisation dependence of the O K and Cu L3 X-ray absorption edges has been compared for in situ cleaved Bi2Sr2CaCu2O8 and Bi2Sr2CuO6 single crystals. The X-ray absorption spectra were measured by means of total electron yield detection. The spectra show for both crystals that the lowest unoccupied Cu 3d and O 2p orbitals are dominantly oriented parallel to the a-b plane, but also the presence of a small amount of unoccupied orbitals oriented perpendicular to the a-b plane can be deduced from both the O K and Cu L3 absorption spectra. A shift of the order of 0.5 eV between absorption into the in-plane and the out-of-plane Cu 3d orbitals was measured for the Bi2Sr2CaCu2O8 crystal, but no such shift was found for the Bi2Sr2CuO6 crystal.
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| 2. |
- Andersen, Jesper N, et al.
(författare)
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Photoemission Spectroscopy At Max-Lab
- 1991
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Ingår i: Synchrotron Radiation News. - : Informa UK Limited. - 0894-0886 .- 1931-7344. ; 4:4, s. 15-19
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Andersen, J. N., et al.
(författare)
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Surface core-level shifts as a probe of the local overlayer structure : CO on Pd(100)
- 1991
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Ingår i: Physical Review Letters. - 0031-9007. ; 67:20, s. 2822-2825
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Tidskriftsartikel (refereegranskat)abstract
- The bonding energies of the Pd 3d and the C 1s core levels have been studied for the p(2 S 2 × 2) R45°, p(3 s2 × S2) R45°, and p(4 S 2 × S 2) R45°structures of CO on Pd(100). Adsorption of CO shifts the Pd 3d surface emission to higher binding energies with the magnitude of the shift depending almost linearly on the number of Pd to CO bonds; the measured shift per bond is close to 0.5 eV. A direct relation is established between the detailed geometry of the CO overlayer and the changes in the Pd 3d spectra.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Johansson, H. I P, et al.
(författare)
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Core-level shifts on Be(101̄0)
- 1994
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 49:24, s. 17460-17463
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution photoemission study of the Be (101̄0) surface, at a sample temperature of 100 K, is reported. Three surface-shifted Be 1s components are revealed having shifts of -700, -500, and -220 meV. These are interpreted as originating from the first, second, and third plus fourth atomic layers while the bulk signal originates from the fifth and deeper layers. The surface layer shift for this more open Be(101̄0) surface is found to be smaller than for the close-packed Be(0001) surface. Reasons for this unusual behavior are suggested.
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| 8. |
- Johansson, L. I., et al.
(författare)
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Surface core level shift on Be( 112̄0)
- 1994
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 321:3
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Tidskriftsartikel (refereegranskat)abstract
- A photoemission study of the Be(112̄0) surface carried out at a sample temperature of 100 K is reported. A surface shifted Be 1s component, having a shift of - 410 meV, is resolved on this surface. The extracted surface to bulk intensity ratio indicate that this component originates from atoms in the surface layer only. This is opposite to previous observations on both the close-packed Be(0001) surface and the Be(101̄0) surface where sub-surface shifted Be 1s levels were unambiguously identified. Among these three surfaces a surface layer atom is expected to have the lowest coordination on the (112̄0) surface but the surface layer shift is found to be smallest on this surface. Compared to findings on other metals this is unusual and reasons contributing to this behaviour are suggested and discussed.
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| 9. |
- Johansson, L. I., et al.
(författare)
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Three surface-shifted core levels on Be(0001)
- 1993
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Ingår i: Physical Review Letters. - 0031-9007. ; 71:15, s. 2453-2456
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Tidskriftsartikel (refereegranskat)abstract
- The results of a high resolution photoemission study of the Be(0001) surface carried out at temperatures between 100 and 450 K are reported. At 100 K, three distinctly shifted Be 1s levels, exhibiting shifts of -825, -570, and -265 meV, are revealed and interpreted to originate from the three outermost atomic layers. Identification of two subsurface core level shifts and a first layer surface shift of -825 meV is unique among close-packed metal surfaces. Temperature dependent broadening effects observed in the bulk and surface BE 1s peaks are also reported.
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| 10. |
- Wassdahl, N., et al.
(författare)
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Soft x-ray emission studies of adsorbates
- 1992
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Ingår i: Physical Review Letters. - 0031-9007. ; 69:5, s. 812-815
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Tidskriftsartikel (refereegranskat)abstract
- Soft x-ray emission spectroscopy is for the first time applied to surfaces and adsorbates. Surface sensitivity is achieved by employing synchrotron radiation in grazing incidence for the excitation. We present O K emission from adsorbed atomic oxygen on Ni(100) and Cu(100) and molecular CO on Ni(100). The observed spectral features correspond to the occupied 2p partial density of states of the adsorbates.
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