  A review is given of pressure induced valence transitions in f-electron
systems calculated with the self-interaction corrected local spin density
(SIC-LSD) approximation. These calculations show that the SIC-LSD is able to
describe valence changes as a function of pressure or chemical composition. An
important finding is the dual character of the f-electrons as either localized
or band-like. A finite temperature generalisation is presented and applied to
the study of the p-T phase diagram of the alpha to gamma phase transition in
Ce.
