| Popis: |
An analysis is presented of the factors influencing the ion-core potentials experienced by electrons and positrons in CdSe. For electrons, resonances are found for 0 ⩽ E ⩽ 100 eV which are associated with the domination of the attractive electron-ion-core interaction at large distances from the core by the repulsive angular-momentum barriers for successively higher partial waves. The resulting phase shifts vary slowly, however, across a given row of the periodic table. For positrons, the repulsive nature of the positron-ion-core interaction yields similar (and non-resonant) phase shifts for highly diverse species like Cd and Se which occur in different rows of the periodic table. These results are utilized to interpret recently observed differences in electron and positron diffraction from the cleavage faces of CdSe. |
