Anisotropic Compton scattering in LiF using synchrotron radiation

Abstract

Using synchrotron radiation, the electronic momentum distribution is measured with a 0.15 atomic unit resolution in a LiF single crystal for the < 100 > and < 111 > directions. This resolution is about four times better than obtained in γ experiments. The spectrometer uses the LURE-DCI radiation with a channel-cut monochromator, a focusing crystal analyser and a position sensitive detector. The measurements performed confirm the significant anisotropy of the electron distribution in LiF. The present results are compared with calculated anisotropies in the range 0 to 2 a.u. ; they agree quite well with the Berggren et al. calculations (LCAO) for q < 0.6 a.u. and with the Euwema et al. calculations (H.F.) for q > 0.7 a.u.