Study of momentum-transfer dependence of Boron K-edge by means of x-ray Raman scattering.

S. A. CEPPI; O. A. PAREDES MELLONE; G. STUTZ

Campinas

Congreso; 24º Reunión anual de usuarios; 2014

LNLS

Inelastic x-ray scattering spectra have been measured for energy losses around the B K-edge in a polycrystalline sample. The B K-edge was investigated for momentum transfers $q$ going from $qa1$, where $a$ is the orbital radius for the K shell. The experiments were measured at XDS beamline using a high energy-resolution spectrometer for inelastic x-ray scattering spectroscopy. The experimental x-ray Raman spectra show clear differences between spectra measured for different momentum transfers, which are related to deviations from the dipole approximation of the x-ray Raman scattering process. In order to explain these differences, \emph{ab initio} theoretical calculations were performed of the projected density of state and also of $q$-dependent Raman spectra using the FEFF 9.6 program. Main changes at high momentum transfers can be assigned to the contribution of monopole transitions to s-type empty states.