Momentum-transfer dependence of the near edge structure of Li

The dynamic structure factor S(q, ω) of the K-electrons in Li metal was measured in an inelastic X-ray scattering experiment with 0.8 eV resolution using synchrotron radiation. The near edge structure of S(q, ω) over an energy range of 30 eV from the edge has been obtained for values of qa of 0.22, 0.38, 1.17 and 1.55, where ℎq is the momentum-transfer and a is the K-electron orbital radius. The overall shape of the near edge region changes remarkably with q. On the other hand, the near edge fine structure varies hardly with q and is similar to the soft X-ray absorption near edge fine structure over a wide range of q. This weakly q-dependent fine structure can be attributed to the band structure effecting the final state electron symmetry, while the strongly q-dependent overall shape may be influenced mainly by the initial momentum distribution of the K-electrons. (author)