Toimub neljapäeval 26. septembril 2013. a., algus kell 16.15 TÜ Füüsika Instituudi (Riia 142) 1. korruse saalis
TÜFI Röntgenspektroskoopia labori doktorant
Soft X-ray spectroscopy of insulators
Isolaatorite spektroskoopia pehme röntgenkiirguse abil (doktoritöö materjalid)
Work done during the PhD studies will be presented. The focus of the talk will be on resonant inelastic scattering experiments (RIXS). Both experimental and theoretical work on some beryllium and boron compounds including BeO, Be2SiO4, BeAl2O4, Be3Al2Si6O18, BN, BBO, LBO, La2Be2O5, Li6YB3O9, Li6GdB3O9, and Y2SiO5 has been carried out. RIXS studies show that a boron core exciton level exists in both LBO and BBO, similarly to BN and B2O3.
The most important part of the work is the study of the phonon relaxation effect in solids. Namely, in some systems (BeO, BBO, Be2SiO4 etc.) a energy loss tail to the elastic scattering line can be observed in the X-ray scattering spectra. A similar phenomenon in the optical region is known as hot luminescence. A simple model to account for the shape of the relevant emission band was developed. Also, the strength of the phonon relaxation effect was shown to be empirically well predicted by the electron-phonon interaction strength.