IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Near edge structure at the lithium K-edge in LiH by inelastic X-ray scattering
Autor/es:
STUTZ, GUILLERMO EDUARDO; PAREDES MELLONE, OSCAR ARIEL; CEPPI, SERGIO ANDRÉS; ARNEODO LAROCHETTE, PIERRE PAUL
Lugar:
Campinas, Brasil
Reunión:
Workshop; 25th RAU Annual Users Meeting LNLS/CNPEM; 2015
Resumen:
The excitation of core electrons of Li in LiH was studied by means of inelastic x-ray scattering spectroscopy (IXSS) at low and high momentum transfer. Measurements were carried out at the XDS beamline of LNLS. A Johann type spectrometer based on a spherical analyzer crystal [1] was used. The core electron contribution was extracted from the whole electronic excitation spectrum. At low momentum transfer the near edge fine structure of the spectrum is interpreted in terms of dipole allowed transitions to empty states. At higher momenta an additional structure was observed, which was assigned to the opening of excitation channels other than dipolar. A chemical shift of the Li K-edge of 2.2 eV to higherenergies relative to Li metal was measured. Calculation of the density of states and simulations of the excitation spectrum were made using the FEFF code [2]. Core-hole effects were found to be appreciable and need to be taken into account in the simulations in order to reproduce the observed spectral features. The present experiment demonstrates the feasibility of investigating near edge structures of light elements by means of IXSS with high energy resolution at the XDS beamline.[1] G. Tirao, G. Stutz, C. Cusatis, J. Synchrotron Rad. 11, 335 (2004). [2] J.J Rehr, J.J. Kas, F.D. Vila,, M.P. Prange, K. Jorissen, Phys.Chem. Chem. Phys., 12, 5503-5513 (2010).