title: Lattice vibrations and electronic transitions in the rare-earth metals: praseodymium under pressure.
abstract: Praseodymium was investigated by Raman spectroscopy under pressure. A negative pressure shift of the E(2g) mode is observed in the dhcp phase, which indicates that the initial structural sequence hcp-->Sm-type-->dhcp-->fcc as a whole in the regular lanthanides is associated with a softening of this mode. The pressure response of the phonon modes, observed in the monoclinic and alpha-uranium phases, where 4f bonding becomes important, is characteristic for anisotropic bonding properties.
authors.affiliation: Department of Earth Sciences, University of Oxford, Oxford OX1 3PR, UK.
authors.forename: Helmut
authors.initials: H
authors.lastname: Olijnyk
authors.forename: Walter A
authors.initials: WA
authors.lastname: Grosshans
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Jephcoat