The sub-bandgap energy loss satellites in the RIXS spectra of beryllium compounds

作者：Kuusik I^*; Kaeaembre T; Kooser K; Pustovarov V; Ivanov V; Kukk E; Kikas A

来源：Journal of Electron Spectroscopy and Related Phenomena, 2011, 184(7): 366-370.

DOI：10.1016/j.elspec.2011.02.002

• RIXS
• Core exciton
• Hot luminescence

Resonant X-ray inelastic scattering spectra have been measured in BeO, phenakite (Be(2)SiO(4)) and chrysoberyl (BeAl(2)O(4)) with the excitation energy near the beryllium K edge.
The RIXS spectra excited in the vicinity of the Be is core resonance show two principal features: the scattering on a valence excitation (which at higher excitation energies verges into the characteristic K emission), and a remarkably strong energy loss sideband to the elastic scattering peak. The energy loss shoulder appears to result from lattice relaxation in the absorption site. The comparison of the RIXS spectra of phenakite, chrysoberyl and BeO shows that the strength of the low energy sideband differs greatly; it is strongest in BeO and weakest in phenakite. The Si 2p RIXS spectra of phenakite also display a similar strong sub-bandgap energy loss tail.
To gain further insight to this process, transitions in a system with a single vibrational mode have been modelled. The phonon relaxation has been simulated empirically by "smearing" the photoabsortion-populated vibrational levels with lower levels. This simple model is able to qualitatively explain this wide energy loss shoulder.

• 出版日期2011-7