A STUDY OF CHARGE-TRANSFER IN VAPOR-DEPOSITED MG-V CRYSTALLINE ALLOYSVIA CHANGES IN AUGER PARAMETERS

An analysis of variations in the Auger parameters of vapour deposited Mg-V alloys with nominal compositions 0.48, 2.95, 8.9 and 15at.% V has been undertaken in order to investigate the electronic changes that t ake place upon alloying Mg with V. The presence of vanadium in the Mg- V system required certain assumptions to be made in the calculations a s a result of the electronic configuration of the valence band of V. C harge transfer from Mg to V as well as changes in the V d charge were calculated by measuring the ME and V Auger parameters and using the ch arge transfer model of Thomas and Weightman. The application of Thomas and Weightman's approach is shown to have advantages over the use of core ionization energy shifts in combination with the potential model. With the use of the Auger parameter there is no need for explicit ene rgy referencing of the core levels and, moreover, in the improved mode l the Madelung or surface dipole contributions are not required unlike in the potential model. An attempt has also been made to understand t he metallurgical significance of charge transfer in terms of the tende ncy for ordering or disordering of solid solutions.