A high-resolution Compton scattering study of Cu: experiment and theory

LDA and GGA Investigations of Some Ground-State Properties and the Compton Profile of Copper with the All-Electron MAPW Method

“…To make this more clear in Figure 2 the differences between the theoretical, either corrected according Lam Platzman or not, and the measured profiles are plotted. The uncorrected results, displayed by the broken curve behave quite similarly as the profiles derived with the KKR scheme [7]: at low momenta the difference amounts almost up to 0.28, after a crossover around 1.0 a.u. the deviations reach −0.07 and approach the value 0.02 near 8.0 a.u, all in electrons/Bohr.…”

“…In the following subsections, the directional Compton profiles are investigated. A critical comparison with previous Kohn-Korringa-Rostocker (KKR) studies by Sakurai et al [7] concludes the work.…”

“…these corrections are almost negligible. Different from the cases of Li [13] and Al [12], they are smaller but not negligible as assumed in [7] and both parameterizations produce similar corrections. The results displayed in Figure 2 are obtained within the LDA and the [Ne]-core but the other cases behave similarly, within the LP corrections according to [46] included, dotted curve: LP corrections according to [47] included, broken curve: LP corrections excluded, dashed-dotted curve: spherical average of the CPs along the principal directions, and long-broken curve: APW result [48].…”

“…Again we find confirmed that the LP corrections which are based on the same functional j i apply to the all-electron profiles. The Compton profiles of the valence electrons along the three principal directions have been obtained by Sakurai et al [7] by subtracting the KKR core contributions from the measured values. Using the weights quoted in Section 2 of the previous work [12] the spherical average of the valence profiles has been derived up to q = 8 a.u.…”

“…This procedure only produces a truncation error from the nonspherical contribution of the EMD which is roughly by the factor 10 smaller than the mean value. This consideration also allows a rough estimate of the accuracy of the KKRcalculations [7] which are based on the EMD evaluated on a mesh generated by 2421 reciprocal lattice vectors extending to about 13.0 a.u., an upper limit markedly different from 20.0 quoted by these authors. (In the fcc reciprocal lattice the last shell includes 2421 reciprocal lattice vectors of the type (10, 6, 6) yielding a p vector of maximal length (172.0)(2π/a)).…”