A study of charge transfer in vapour deposited Mg—V crystalline alloys via changes in Auger parameters

Abstract

An analysis of variations in the Auger parameters of vapour deposited Mg—V alloys with nominal compositions 0.48, 2.95, 8.9 and 15 at.% V has been undertaken in order to investigate the electronic changes that take place upon alloying Mg with V. The presence of vanadium in the Mg—V system required certain assumptions to be made in the calculations as a result of the electronic configuration of the valence band of V. Charge transfer from Mg to V as well as changes in the V d charge were calculated by measuring the Mg and V Auger parameters and using the charge 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 energy referencing of the core levels and, moreover, in the improved model the Madelung or surface dipole contributions are not required unlike in the potential model. An attempt has also been made to understand the metallurgical significance of charge transfer in terms of the tendency for ordering or disordering of solid solutions.