Core-level binding-energy shifts at surfaces and in solids

Electron spectroscopy - an outlook

X-ray photoelectron spectra (XPS) and $\mathrm{Al} K$ and $\mathrm{Al} {L}_{2,3}$ soft-x-ray spectra (SXS) of valence bands for aluminum-noble-metal alloys are rationalized on the basis that SXS spectra are dominated by dipole selection rules while XPS spectra chiefly reflect the noble-metal $d$ bands. We find, in agreement with theory, that the main peaks in the $\mathrm{Al} 3s$ partial densities of states are at higher binding energy than those for the noble metal $d$ states. Peaks in the $\mathrm{Al} 3p$ partial densities of states approximately coincide with the higher-energy peaks in the partial densities of noble-metal $d$ states. The remarkable large chemical shifts of core levels in these alloys are noted and the $\mathrm{Au} {N}_{6,7}$ SXS emission from aluminum-noble-metal alloys also discussed. The Auger spectra from Al-Ag and Al-Cu alloys provide strong additional evidence that single-atom effects dominate in the Auger processes for these alloys.

Electronic structure of aluminum and aluminum-noble-metal alloys studied by soft-x-ray and x-ray photoelectron spectroscopies

KLL, and KLM Auger and X-ray photoelectron spectra for pure magnesium, for Mg2Cu, Mg3Au and Mg3Bi2, and for MgO are reported. Assignments are made for almost all of the observed features in the Auger spectra. For the pure metal, internal photoemission peaks and a plasmon gain peak are shown to be present in the X-ray excited spectra.

http://iopscience.iop.org/article/10.1088/0305-4608/5/2/020/pdf

X-ray excited Auger and photoelectron spectra of magnesium, some alloys of magnesium and its oxide

We have investigated various silica zeolites using density functional theory with periodic supercells, plane waves, and pseudopotentials. These zeolitic phases include silica sodalite, chabazite, mordenite, silica LTA, and silicalite. Atom-level geometries, elastic properties, and cohesive energies are presented. Although the zeolites exhibit a wide range of Si−O−Si angles and densities, the cohesive energies remain nearly constant. The elastic properties vary significantly from one phase to another, and in some cases, large elastic anisotropies are observed.

/pdf/density-functional-theory-study-of-silica-zeolite-structures-4amnds7ldi.pdf

L.M. Watson

Papers

Valence bands of aluminium noble-metal alloys studied by X-ray photoelectron spectroscopy

Soft x-ray spectra and electronic structure of aluminium-gold alloys