Abstract
The present thesis is concerned with the theoretical study of xray photoemission spectra from clean and adsorbatecovered metal surfaces. The main tool is ab initio density functional (DFT) total energy calculations. The first part gives an overview of the theoretical treatment of xray photoemission with our present contributions highlighted, and an introduction to DFT theory and computational techniques for obtaining total energies.
The second and main part of the thesis contains the original research papers. In a major part of these, DFT calculations are combined with and compared to experimental photoemission spectra in order to investigate both the local geometric as well as electronic structure. Paper I and II consider clean and COcovered Rh(111) surfaces, paper IV considers the clean Al(100) and Al(111) surfaces both theoretically and experimentally, and paper V combines experimental techniques and theoretical modeling to investigate the adsorption of Na on Al(100) in a (sqrt(5) x sqrt(5))R27 structure. In all cases we find that ab initio calculations predict the experimental findings well, both with regard to geometries and with regard to chemical shifts and other electronic properties. Furthermore, we find that chemical shifts usually depend on the local geometry in a rather sensitive way. Thus, by combining experiment with theoretical modeling, very precise geometrical information can be obtained.
In paper III, we leave the common approximation of treating the coreelectron vacancy as a structureless entity as in the MahanNozièresDeDominicis (MND) model and takes its internal spin and possible orbital angular momentum degrees of freedom into account. We treat the additional symmetrydependent interactions by leading order cumulant and self energy expansions and apply our theory to both an spbonded metal (Al (2p)) as well as 4d metals (Rh (3d), Pd (3d)). In the case of Al and Pd the effects of corelevel degeneracy are small, but for Rh we find important modifications. When the effects of corelevel degeneracy are included, the theoretical lineshapes agree rather well with experiment.
The second and main part of the thesis contains the original research papers. In a major part of these, DFT calculations are combined with and compared to experimental photoemission spectra in order to investigate both the local geometric as well as electronic structure. Paper I and II consider clean and COcovered Rh(111) surfaces, paper IV considers the clean Al(100) and Al(111) surfaces both theoretically and experimentally, and paper V combines experimental techniques and theoretical modeling to investigate the adsorption of Na on Al(100) in a (sqrt(5) x sqrt(5))R27 structure. In all cases we find that ab initio calculations predict the experimental findings well, both with regard to geometries and with regard to chemical shifts and other electronic properties. Furthermore, we find that chemical shifts usually depend on the local geometry in a rather sensitive way. Thus, by combining experiment with theoretical modeling, very precise geometrical information can be obtained.
In paper III, we leave the common approximation of treating the coreelectron vacancy as a structureless entity as in the MahanNozièresDeDominicis (MND) model and takes its internal spin and possible orbital angular momentum degrees of freedom into account. We treat the additional symmetrydependent interactions by leading order cumulant and self energy expansions and apply our theory to both an spbonded metal (Al (2p)) as well as 4d metals (Rh (3d), Pd (3d)). In the case of Al and Pd the effects of corelevel degeneracy are small, but for Rh we find important modifications. When the effects of corelevel degeneracy are included, the theoretical lineshapes agree rather well with experiment.
Original language  English 

Qualification  Doctor 
Awarding Institution 

Supervisors/Advisors 

Award date  2002 Sep 30 
Publisher  
ISBN (Print)  9162853554 
Publication status  Published  2002 
Bibliographical note
Defence detailsDate: 20020930
Time: 13:15
Place: Lecture Hall F, Department of Physics
External reviewer(s)
Name: Ågren, Hans
Title: Prof
Affiliation: KTH

Article: Densityfunctional theory applied to Rh(111) andCO/Rh(111) systems: geometries, energies and chemical shiftsM. Birgersson, C.O. Almbladh, M. Borg and J. N. Andersen,submitted to Physical Review B
Article: Densityfunctional theory applied to the CO/Rh(111) system: molecular vibrationsM. Birgersson, C.O. Almbladh, M. Borg and J. N. Andersen,to be submitted to Physical Review B
Article: Effects of corelevel degeneracies and crystal fields on corelevel spectraM. Birgersson and C.O. Almbladh,to be submitted to Physical Review B
Article: Experimental and theoretical surface corelevel shifts of aluminum (100) and (111)M. Borg, M. Birgersson, M. Smedh, A. Mikkelsen, D. L. Adams,R. Nyholm, C.O. Almbladh and J. N. Andersen,to be submitted to Physical Review B
Article: Structure and formation of the Al(100) (sqrt(5) x sqrt(5))R27 Na phase: A LEED, DFT and HRCLS studyM. Borg, A. Mikkelsen, M. Birgersson, M. Smedh, E. Lundgren,D. L. Adams, C.O. Almbladh and J. N. Andersen,accepted for publication in Surface Science
Subject classification (UKÄ)
 Condensed Matter Physics
Keywords
 chemical shifts
 density functional theory
 Condensed matter:electronic structure
 electrical
 magnetic and optical properties
 supraconductors
 magnetic resonance
 relaxation
 Atomic and molecular physics
 spektroskopi
 magnetisk resonans
 supraledare
 magnetiska och optiska)
 egenskaper (elektriska
 spectroscopy
 Kondenserade materiens egenskaper:elektronstruktur
 corelevel photoemission
 single crystal surfaces
 Atom och molekylärfysik
 Fysicumarkivet A:2002:Birgersson
 corehole degeneracies
 metal surfaces
 adsorption
 molecular vibrations