Lattice vibrations and electronic transitions in the rare-earth metals: Praseodymium under pressure

• Published in: Physical review letters Vol. 93; no. 25; pp. 255505.1 - 255505.4
• Main Authors: OLIJNYK, Helmut, GROSSHANS, Walter A, JEPHCOAT, Andrew P
• Format: Journal Article
• Language: English
• Published: Ridge, NY American Physical Society 17-12-2004
• Subjects: Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Lattice dynamics; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; Solid-solid transitions; Specific phase transitions; Raman spectra; FCC lattices; Pressure effects; Phase transformations; Rare earths; Vibrational modes; Chemical bonds; HCP lattices; Lattice vibrations; Lattice parameters; Soft modes; Praseodymium
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.93.255505

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.