Dimensional factor effect on electron structure of uranium in intermetallic compounds

Dependence of chemical displacements of X-ray Lα1-, Lβ2-and Lγ1 - lines of uranium (UF3 reference point) for certain intermetallic compounds on the distance between the nearest uranium atoms (rU-U)) was studied experimentally. Linear dependence of displacement of all the three lines studied on rU-U for compounds with rU-U ≤ 3.4 A, whereas for compounds with rU-U > 3.4 A the regular dependence is not observed. It is assumed that at small U-U distances 5f-electron is delocalized and is in hybridized state with 6d-, 7s- or 7p-electrons, while in compounds with rU-U > 3.4 A it can attain localized character, which agrees with the Hill rule and modern notions on the nature of 5f-electrons. 14 refs.; 2 figs.; 2 tabs