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High-Pressure Equation of State for Partially Ionic SolidsRecently, we showed that the cohesive energy of partially ionic solids may be characterized by a two-term energy relationship consisting of a Coulomb term arising from the valence-charge transfer delta Z between the atoms, and a scaled universal energy function E(sup *)(a(sup *)), which accounts for the partially covalent character of the bond and for the repulsion between the atomic cores for small R; a(sup *) is a scaled length. Normalized cohesive-energy curves of alkali halide crystals and of Ti and Ag halide crystals were obtained, and the cohesive-energy-curve parameters were used to generate theoretical equation-of-state (EOS) curves for the Li, Na, K, Cs, and Ag halides. Good agreement was obtained with the experimental isothermal compression curves over a wide pressure range (0-90 kbar). In this paper we verify that the cohesive-energy relationship is valid for divalent partially ionic solids; physically reasonable charge-transfer values (1.80 less than delta Z less than 2.0) are obtained for MgO, CaO, and CaS. Next, EOS curves for LiF, NaF, Nal, CsCl, Csl, MgO, CaO, and CaS are generated in terms of the cohesive-energy parameters. These EOS's yield excellent fits to experimental isothermal-compression data and to shock-wave data to very high pressures (P(sub max)= 250-1350 kbar).
Document ID
19970020068
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Schlosser, Herbert
(Cleveland State Univ. Cleveland, OH United States)
Ferrante, John
(NASA Lewis Research Center Cleveland, OH United States)
Date Acquired
August 17, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Physical Review B
Publisher: The American Physical Society
Volume: 48
Issue: 9
ISSN: 0163-1829
Subject Category
Inorganic And Physical Chemistry
Report/Patent Number
NAS 1.15:112330
NASA-TM-112330
Accession Number
97N71924
Distribution Limits
Public
Copyright
Public Use Permitted.
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