| 1. |
- Andersen, Jesper N., et al.
(författare)
-
Core level binding energy shifts in interfaces between 4d and alkali metals
- 1995
-
Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 75:C, s. 225-232
-
Tidskriftsartikel (refereegranskat)abstract
- High resolution core level photoemission measurements are reported of the binding energy shifts of the 3d core level of Mo, Rh and Pd atoms in interfaces between these 4d metals and alkali metals. The core level binding energies of the interface 4d atoms are found to be almost equal to those of the clean surface atoms for Mo and Rh. For Pd a large alkali induced shift towards higher binding energy is found. The implications of these results for the information derivable from core level binding energy shifts in metallic interfaces are discussed and it is demonstrated that the present results are explained by established total energy based models for core level binding energy shifts in metallic systems.
|
|
| 2. |
- Andersen, Jesper N, et al.
(författare)
-
Strong Phonon Replicas in Be 1 s Photoemission Spectra
- 2001
-
Ingår i: Physical Review Letters. - 1079-7114. ; 86:19, s. 4398-4401
-
Tidskriftsartikel (refereegranskat)abstract
- The Be 1s core level photoemission line from metallic Be is shown to contain unexpected internal fine structure. We argue that this fine structure is caused by intrinsic excitation of a narrow band of optical phonons in the 1s photoemission process. The general importance of the present results for high resolution core level photoemission investigations of metals is pointed out.
|
|
| 3. |
- Borg, Mikael, et al.
(författare)
-
Experimental and theoretical surface core-level shifts of aluminum (100) and (111)
- 2004
-
Ingår i: Physical Review B. - 1550-235X. ; 69
-
Tidskriftsartikel (refereegranskat)abstract
- The surface core-level shifts of Al(111) and Al(100) have been measured using high-resolution core-level photoemission spectroscopy and calculated using density functional theory (DFT). For Al(100), the 2p core-level shift of the first (second) layer was determined to be –75 meV (+20 meV) from experiment and –71 meV (+20 meV) from the DFT calculations. For Al(111), the corresponding values are –27 meV (0 meV) from experiment and –14 meV (–) from the DFT calculations. Core-level splittings caused by the low-symmetry crystal fields at the (111) and (100) surfaces have also been studied. These splittings turn out to be much smaller than previously reported provided proper care is taken of the influence of the core hole screening and of core–valence exchange beyond the DFT level. Finally, the experimental Al 2p line shape was found to contain structure caused by a sharp no-phonon line and a broad and weak phonon replica.
|
|
| 4. |
- Colakerol, L, et al.
(författare)
-
Resonant photoemission at the Ga 3p photothreshold in InxGa1-xN
- 2006
-
Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 152:1-2, s. 25-28
-
Tidskriftsartikel (refereegranskat)abstract
- Resonance effects at the Ga 3p photoabsorption threshold have been observed in photoemission spectra recorded from thin film InxGa1-xN alloys. The spectra display satellites of the main Ga 3d emission line, and the intensity of these satellites resonate at this threshold. The satellites are associated with a 3d(8) state, and have previously been observed for the semiconductors GaN, GaAs, and GaP. The resonance behavior has been studied for a variety of InxGa1-x thin films with differing In concentration and band gap. The photon energy where the maximum resonance is observed varies with band gap within the alloy system, but does not follow the trend observed for binary Ga semiconducting compounds. We also observe that the threshold resonant energy increases slightly as the In content increases. (c) 2006 Elsevier B.V. All rights reserved.
|
|
| 5. |
- Grizolli, Walan, et al.
(författare)
-
Multilayer based soft-x-ray polarimeter at MAX IV Laboratory.
- 2016
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 87:2
-
Tidskriftsartikel (refereegranskat)abstract
- A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.
|
|
| 6. |
- Grizolli, Walan, et al.
(författare)
-
Use of astigmatic re-focusing at HP-XPS end-station
- 2013
-
Ingår i: 11th International Conference on Synchrotron Radiation Instrumentation (SRI 2012). - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 425
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present the refocusing optics for the new high pressure photoelectron spectroscopy (HP-XPS) branch line at MAX-lab, based on a plane grating monochromator with vertically collimated beam. For the HP-XPS instrument, the required spot size is dictated by the small geometric acceptance of the HP-XPS electron energy analyzer. Whereas a pair of bendable mirrors in a KB configuration has some advantages as refocusing elements, we have studied whether similar performance can be achieved with a single non-bendable mirror. In this solution, however, the need for strong horizontal magnification results in a strong vertical magnification and into a very asymmetric image, the height being just a fraction of the width. We have studied through an analytical geometrical model and ray tracing simulations the use of astigmatism to increase the vertical beam size up to the geometric acceptance of the detector. As a result the vertical beam size at sample plane is mostly determined by the photon angular distribution and is not dependent on the exit slit aperture size. In addition the vertical beam size can be controlled by the grating c(ff) parameter, making possible to adjust the photon density and minimize sample damage by the radiation.
|
|
| 7. |
- Kurtz, Richard L., et al.
(författare)
-
Core-excitoninduced desorption from MgO
- 1987
-
Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 35:14, s. 7794-7797
-
Tidskriftsartikel (refereegranskat)abstract
- Core-exciton-induced desorption of O and H from MgO(100) and MgO(111) has been observed using photon excitation energies spanning the O K edge. Electron-yield data from partially oxidized Mg implies that these states are localized in the near-surface region. O and H desorption results from the decay of different O core-exciton states as well as the states produced by interband transitions. The O excitonic levels are interpreted in terms of their related atomic origin.
|
|
| 8. |
- Lundgren, Edvin, et al.
(författare)
-
Geometry of the valence transition induced surface reconstruction of Sm(0001).
- 2002
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 88:13, s. 136102-136102
-
Tidskriftsartikel (refereegranskat)abstract
- We present a structural determination of the surface reconstruction of the Sm(0001) surface using surface x-ray diffraction, scanning tunneling microscopy, and ab initio calculations. The reconstruction is associated with a large (22%) expansion of the atomic radius for the top monolayer surface Sm atoms. The mechanism driving the surface reconstruction in Sm is unique among all elements and is connected to the strong correlations of the 4f electrons in Sm and the intermediate valence observed in certain Sm compounds. The atoms constituting the top monolayer of Sm(0001) have vastly different chemical properties compared to the layer underneath and behave as if they were an adsorbate of a different chemical species.
|
|
| 9. |
- Mancini, Derrick C., et al.
(författare)
-
Design of a compact varied-line space grating monochromator for enhanced flux at MAXLAB
- 1995
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 66:2, s. 2157-2159
-
Tidskriftsartikel (refereegranskat)abstract
- For soft x-ray fluorescence spectroscopy with selective energy excitation, it is desirable to have maximum flux at moderate resolution. A plane grating monochromator with varied line spacing can be used in the convergent beam of an ellipsoidal focusing mirror to provide moderate resolution with a large collection angle and minimum number of reflecting surfaces. We determine the design parameters for a varied-line-space grating monochromator to provide light in the 200-1000 eV range. The results of modeling are discussed with respect to the optimal choices of monochromator for our experimental requirements. A novel mechanical design is proposed for constructing the monochromator in a compact form with the minimum number of moving parts and alignments.
|
|
| 10. |
|
|
| 11. |
- Nyholm, Ralf, et al.
(författare)
-
N-shell core-level widths for the elements W74 to Bi83
- 1987
-
Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 36:1, s. 20-24
-
Tidskriftsartikel (refereegranskat)abstract
- The Lorentzian lifetime widths of the 4d and 4f levels in the sixth-period elements W74 to Bi83 have been measured using photoelectron spectroscopy. A compilation of 4f-level widths from the literature is also made. The general trend of the 4f-level widths is well reproduced by McGuires calculations, although the absolute widths seem to be underestimated. The 4d5/2-level width shows a remarkable constancy over the whole series of elements and it varies only between 3.6 and 4.0 eV for all the investigated elements. The determined 4d level widths are well reproduced by recent calculations by Ohno and Wendin. Special attention has been paid to lifetime broadenings which are characteristic for the solid phase. Such broadenings are observed for the 4d3/2 level due to N4N5O45 Coster-Kronig processes. In the 4f shell a small Coster-Kronig broadening is also observed in the beginning of the series.
|
|
| 12. |
- Plucinski, L, et al.
(författare)
-
Resonant shake-up satellites in photoemission at the Ga 3p photothreshold in GaN
- 2005
-
Ingår i: Solid State Communications. - : Elsevier BV. - 1879-2766 .- 0038-1098. ; 136:4, s. 191-195
-
Tidskriftsartikel (refereegranskat)abstract
- Photoemission spectra recorded near the Ga 3p photothreshold from GaN have been found to contain satellites of the main Ga 3d emission line. The intensity of these satellites resonate at this threshold, and are associated with a 3d(8) state. The correlation energies and binding energies for the satellite multiplet have been measured for the satellite and related Auger transitions. The satellite multiplet contains additional constant binding energy features not observed in previous studies of other Ga compounds. The present results are compared with those for Gal? and GaAs.
|
|
| 13. |
- Sankari, R, et al.
(författare)
-
Update of the Finnish-Swedish beam line I411 at MAX-lab: Simulations of expected performance
- 2006
-
Ingår i: Proceedings of the 20th International Conference on X-ray and Inner-Shell Processes (Radiation Physics and Chemistry). - : Elsevier BV. - 0969-806X. ; 75:11, s. 2000-2003
-
Konferensbidrag (refereegranskat)abstract
- In the modified SX-700 monochromator installed at beam line I411, the focusing before the exit slit is achieved by a plane elliptical mirror. Like in the original SX-700 design, the resolution is mainly limited by the slope errors of the focusing mirror. A simple method to improve the resolution is to replace the focusing mirror by one with smaller slope errors. The effects of replacing the refocusing mirror by similar but more accurate in shape are studied both by carrying out ray tracing simulations and by analytical approach. Also the effect of replacing the grating was studied. (c) 2006 Elsevier Ltd. All rights reserved.
|
|
| 14. |
- Schäfers, Franz, et al.
(författare)
-
Soft-x-ray polarimeter with multilayer optics : Complete analysis of the polarization state of light
- 1999
-
Ingår i: Applied Optics. - 1559-128X. ; 38:19, s. 4074-4088
-
Tidskriftsartikel (refereegranskat)abstract
- The design of a versatile high-precision eight-axis ultrahigh-vacuum-compatible polarimeter is presented. This multipurpose instrument can be used as a self-calibrating polarization detector for linearly and circularly polarized UV and soft-x-ray light. It can also be used for the characterization of reflection or transmission properties (reflectometer) or polarizing and phase-retarding properties (ellipsometer) of any optical element. The polarization properties of Mo/Si, Cr/C, Cr/Sc, and Ni/Ti multilayers used in this polarimeter as polarizers in transmission and as analyzers in reflection have been investigated theoretically and experimentally. In the soft-x-ray range, close to the 2p edges of Sc, Ti, and Cr, resonantly enhanced phase retardation of the transmission polarizers of as much as 18° has been measured. With these newly developed optical elements the complete polarization analysis of soft-x-ray synchrotron radiation can be extended to the water-window range from 300 to 600 eV.
|
|
| 15. |
- Stråhlman, Christian, et al.
(författare)
-
A Tandem Time--of--Flight Spectrometer for Negative--Ion/Positive--Ion Coincidence Measurements with Soft X-ray Excitation
- 2016
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 87:1
-
Tidskriftsartikel (refereegranskat)abstract
- We present a newly constructed spectrometer for negative--ion/positive--ion coincidence spectroscopy of gaseous samples. The instrument consists of two time--of--flight ion spectrometers and a magnetic momentum filter for deflection of electrons. The instrument can measure double and triple coincidences between mass--resolved negative and positive ions with high detection efficiency. First results include identification of several negative--ion/positive--ion coincidence channels following inner-shell photoexcitation of sulfur hexaflouride (SF$_6$).
|
|
| 16. |
- Stråhlman, Christian, et al.
(författare)
-
Angle-resolved time-of-flight spectroscopy applied to multi-bunch operation at MAX-lab: a design study
- 2013
-
Ingår i: IOP Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 425
-
Konferensbidrag (refereegranskat)abstract
- Angle-resolved time-of-flight (ARTOF) spectrometers have found use in a number of applications, including ARPES. However, the fundamental requirement of an external start trigger matching the read-out time of the instrument limits its usability at many storage rings. Hitherto all reported experiments have been performed at storage rings capable of running in single-bunch mode. To eliminate this restriction, we propose a method where a pulsed electronic gate is introduced to allow for ARTOF usage at normal multi-bunch operation of the MAX II storage ring. This paper will show the working principle and outline the design for this technique.
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Söderholm, S, et al.
(författare)
-
A photoemission spectroscopy and X-ray absorption study of Bi(2)Sr(2)CaCu(2)O(8) single crystal with adsorbed Cs: On the origin of states affected by electron doping and evidence for spatially resolved electron doping
- 1996
-
Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 8, s. 1307-1320
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of electron doping, via deposition of small amounts of Cs, on the electronic structure of has been studied by high-resolution photoelectron spectroscopy (PES) and x-ray absorption spectroscopy (XAS), utilizing synchrotron radiation. The changes in the electronic structure were monitored by PES of the valence band and of the O 1s, Bi 4f, Bi 5d, Ca 2p and Sr 3d core levels, and by XAS at the O 1s, Cu 2p and Ca 2p edges. The experimental data suggest that the loss of the Fermi edge and the loss of spectral intensity down to about 2 eV below the Fermi level, and the substantial loss of spectral intensity of the pre-edge structure in the O 1s XAS spectrum are mainly due to annihilation of states with O 2p character in the Cu - O layer. It is evident from bulk- and surface-sensitive XAS spectra that the electron doping by Cs affects the electronic structure more strongly close to the surface. This implies that the doping occurs locally and that the charge transfer between the different layers in the unit cell is not uniform. Thus it seems possible to alter the electronic properties of locally through spatially resolved electron doping. When larger amounts of Cs are deposited, a chemical reaction occurs which causes a disruption of the Bi - O layer. This deposition regime is characterized by the presence of caesium oxide and reduced (metallic) Bi.
|
|
| 20. |
- Thiagarajan, Balasubramanian, et al.
(författare)
-
The Normal Incidence Monochromator Beamline I3 on MAX III
- 2010
-
Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1234, s. 661-664
-
Konferensbidrag (refereegranskat)abstract
- On the 700 MeV MAX III ring at MAX-lab, a 6.65 m off-axis eagle type monochromator beamline has recently been commissioned. The beamline is sourced by an apple type variable polarization undulator. The energy range of the beamline is 4.6-50 eV and the resolving power achieved is more than 100,000. There are two branch lines, one for angle and spin resolved photoemission studies from solids and the other for gas phase and luminescence experiments. We present the design and performance of the beamline.
|
|
| 21. |
- Urpelainen, Samuli, et al.
(författare)
-
The SPECIES beamline at the MAX IV Laboratory : A facility for soft X-ray RIXS and APXPS
- 2017
-
Ingår i: Journal of Synchrotron Radiation. - 1600-5775 .- 0909-0495. ; 24:1, s. 344-353
-
Tidskriftsartikel (refereegranskat)abstract
- SPECIES is an undulator-based soft X-ray beamline that replaced the old I511 beamline at the MAX II storage ring. SPECIES is aimed at high-resolution ambient-pressure X-ray photoelectron spectroscopy (APXPS), near-edge X-ray absorption fine-structure (NEXAFS), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) experiments. The beamline has two branches that use a common elliptically polarizing undulator and monochromator. The beam is switched between the two branches by changing the focusing optics after the monochromator. Both branches have separate exit slits, refocusing optics and dedicated permanent endstations. This allows very fast switching between two types of experiments and offers a unique combination of the surface-sensitive XPS and bulk-sensitive RIXS techniques both in UHV and at elevated ambient-pressure conditions on a single beamline. Another unique property of the beamline is that it reaches energies down to approximately 27 eV, which is not obtainable on other current APXPS beamlines. This allows, for instance, valence band studies under ambient-pressure conditions. In this article the main properties and performance of the beamline are presented, together with selected showcase experiments performed on the new setup.
|
|
