Applications of Multiple Scattering Theory to Electron Spectroscopy

ABSTRACTBecause it gives direct and convenient access to the Green's function, multiple scattering theory (MST) provides a powerful machinery for the calculation of I particle observables in general and electron spectroscopies in particular.The two techniques in which multiple scattering methods have made the biggest impact areangle-resolved photoemission and x-ray spectroscopy (absorption and emission); here the essential point is that MST allows experimental data to be analysed and modelled on the same footing as calculations of the underlying electronic structure, for both ordered and disordered systems. Applications in these areas are briefly reviewed, drawing attention to the two outstanding current deficiencies of the methodology (the use of density functional theory to describe excited states and the approximate — muffin-tin — form of the effective 1—electron potential) as well as its successes.Current developments, particularly the treatment of relativistic and magnetic systems, the possibilities opened up by third-generation synchrotron radiation sources, and the use of parallel computing techniques, are mentioned.