Evidence of Optical Transitions in X-Ray Inelastic Scattering Spectra: Li Metal

We report results of x-ray Compton-Raman scattering experiments. In addition to the expected Compton and Raman scattering, there is a prominent feature in the form of a peak near $\frac{E}{E_{\mathrm{F}}}=1\mathrm{}$. The new peak can be explained qualitatively by considering the conduction band of lithium metal to be composed of hybridized orbital electrons, and it furnishes the first evidence of an $L$-x-ray Raman band.