Crystal structure and optical study of praseodymium polyphosphate Pr(PO{sub 3}){sub 3}
Single crystals of praseodymium polyphosphate Pr(PO{sub 3}){sub 3} were grown for the first time using a flux method and characterized by single-crystal X-ray diffraction. Pr(PO{sub 3}){sub 3} is isostructural with Nd(PO{sub 3}){sub 3} and La(PO{sub 3}){sub 3}. It crystallizes in the orthorhombic system with space group C222{sub 1} (D{sub 2}{sup 5}), with lattice parameters: a=11.234(1) A, b=8.5289(8) A, c=7.3199(8) A. The crystal structure was resolved with final R(F{sup 2})=0.0359 and R{sub w}(F{sup 2})=0.0924 for 402 independent reflections (F{sub 0}{sup 2}{>=}2{sigma}(F{sub 0}{sup 2})). In the Pr(PO{sub 3}){sub 3} structure, oxygen atoms form a PO{sub 4} tetrahedron around each P atom and a PrO{sub 8} polyhedron around each Pr atom. The PO{sub 4} tetrahedra share corners to produce helical chains and the PrO{sub 8} polyhedra share edges to form zigzag chains. The shortest Pr-Pr distance is 4.253 A. The energies of the vibrational modes of the crystal are obtained from the infrared and Raman spectra. Measurements of emission spectra under pulsed laser excitation in the Pr{sup 3+} (4f{sup 2}) {sup 3}P{sub J} (J=0, 1, 2) levels and decay times of the observed emissions are reported both at room and liquid-helium temperatures. X-ray excitation leads to intense ultraviolet 4f{sup 1}5d{sup 1}{yields}4f{sup 2} band emissions in the 200-300 nm spectral range with decay times in the order of 6 ns both at room and low temperatures.
- OSTI ID:
- 20883140
- Journal Information:
- Materials Research Bulletin, Vol. 38, Issue 11-12; Other Information: DOI: 10.1016/S0025-5408(03)00185-5; PII: S0025540803001855; Copyright (c) 2003 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION SPECTROSCOPY
EMISSION SPECTRA
EXCITATION
HELIUM
INFRARED SPECTRA
LATTICE PARAMETERS
LUMINESCENCE
MONOCRYSTALS
ORTHORHOMBIC LATTICES
PHOSPHATES
PRASEODYMIUM
PRASEODYMIUM IONS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SPACE GROUPS
ULTRAVIOLET RADIATION
X RADIATION
X-RAY DIFFRACTION