Many-body effects in metals due to a change in the core electron occupation number appear in a large number of spectroscopies. The possible importance of the core hole has been realized and discussed for a very long time. Mahan's idea of excitons in metals gave the topic strong stimulus. First the interest was focused on threshold singularities in simple metals. The topic was thoroughly discussed in Mahan's 1974 review and declared solved and completed. This declaration was strongly challenged by Dow and collaborators. This has led to a deeper and more detailed understanding. In particular the importance of static core hole effects, of phonons, of electron bandstructure, of exchange coupling (the Onodera effect) and of spindependent phaseshifts has been realized. Thus the longstanding puzzle of the lithium edge now seems to have found its solution in terms of phonons and bandstructure and not in the MND-effect - the broad emission edge can be explained by incomplete phonon relaxation and the broad absorption edge by the one-electron density of states.
|Title of host publication||Le Journale de Physique Colloques|
|Editors||F. COMBET FARNOUX|
|Publisher||J. Phys. Colloques 3|
|Publication status||Published - 1978|