Dichroism in Valence Band X-Ray Photoemission Spectroscopy

As has been demonstrated by various authors an expression for the photo electron current intensity l E,k,ms uj,q, ) observed in VB-photo emission can be derived by 

Here the sum runs over all possible initial states and the operator describes the interaction of the electrons and the radiation field with wave vector q and polarization A. In Eq. (1) it has been assumed that the detector selectively counts photo electrons with energy E, wave vector k, and spin polarization The corresponding final 

If one is dealing with a randomly disordered alloy it is straightforward to perform the necessary configuration average [9]. In the case of one atom per unit cell one ends up with the following expression for the photo current 

Here is the concentration of component a, is the single site t-matrix, Af E) is the scattering path operator and is the matrix element with respect to Xqx- 

The approach presented above has been applied to the disordered alloy system Co,j,Pt], j,. Theoretical spectra for various concentrations are given in Fig. 1 for unpolarized radiation with huj = 1253.6eV. As can be seen, these spectra agree very well 

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