UNIGE document Scientific Article
previous document  unige:3603  next document
add to browser collection

Mixed PbFBr1-xIx crystals: structural and spectroscopic investigations

Rief, A.
Van Mechelen, J.L.M.
Blaha, P.
Published in Journal of Physics. Condensed Matter. 2007, vol. 19, no. 3, p. 36214
Abstract Mixed single PbFBr1−xIx crystals have been prepared. X-ray powder diffraction structure determinations show that all samples crystallize with the matlockite structure. However, the single crystal structure of PbFBr0.5I0.5 involves not only fractional occupation of one site corresponding to the stoichiometry, but also split positions of the Pb2+ ion. Raman spectra reveal the presence of new additional bands with respect to PbFBr and PbFI. DFT calculations of lattice vibrations for PbFI show good agreement with experimental spectra. The calculated phonon dispersion curve suggests that for the mixed crystals the centre of inversion is conserved locally. These combined results suggest the presence of domains with ordered F–Pb–Br–Br–Pb–F and F–Pb–I–I–Pb–F layers in the mixed crystals. Calculations on PbFBr0.5I0.5 show that this suggested structure is more stable than the structure consisting of the F–Pb–Br–I–Pb–F arrangement.
Full text
Research group Groupe Hagemann
(ISO format)
HAGEMANN, Hans-Rudolf et al. Mixed PbFBr1-xIx crystals: structural and spectroscopic investigations. In: Journal of Physics. Condensed Matter, 2007, vol. 19, n° 3, p. 36214. https://archive-ouverte.unige.ch/unige:3603

217 hits



Deposited on : 2009-10-02

Export document
Format :
Citation style :