Evidence for 4<i>f</i>-shell delocalization in praseodymium under pressure

Abstract

Praseodymium metal undergoes a crystallographic phase transformation from a distorted fcc lattice to a distorted hcp structure at a pressure of ≃210 kbar. The phase change is accompanied by a large volume decrease of ≃19%. This decrease is analogous to the volume collapse at the γ-α transition in cerium and thus provides strong evidence for a delocalization of the 4 f2 configuration into a 4f conduction band.