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Thermal Expansion Behaviors of Li 3 AsW 7 O 25 : A Case Study for Comparative Debye Temperature for a Large Polyatomic Unit Cell
Author(s) -
Mangir Murshed M.,
Zhao Pei,
Huq Ashfia,
Gesing Thorsten M.
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700330
Subject(s) - anharmonicity , thermal expansion , debye model , debye , thermodynamics , heat capacity , neutron diffraction , isotropy , debye function , debye–waller factor , raman spectroscopy , polyatomic ion , grüneisen parameter , materials science , condensed matter physics , chemistry , diffraction , crystal structure , physics , debye length , crystallography , ion , quantum mechanics
The thermal expansion behavior of Li 3 AsW 7 O 25 has been studied. The temperature‐dependent development of crystal structural parameters was obtained from Rietveld refinement using neutron time of flight powder diffraction data. Modeling of the lattice thermal expansion was carried out using a Grüneisen first‐order approximation for the zero‐pressure equation of state, where the temperature‐dependent vibrational energy was calculated taking the Debye‐Einstein‐Anharmonicity approach. Temperature‐dependent Raman spectra shed light on some selective modes with unusual anharmonicity. Debye temperatures were calculated using three different theoretical approaches, namely, thermal expansion, mean‐squared isotropic atomic displacement parameter and heat capacity. Similarities as well as discrepancies between the numerical values obtained from different theoretical approaches are discussed.