Accession Number : AD0698331

Title :   COMPRESSIBILITY AND POLYMORPHISM OF SOLIDS.

Descriptive Note : Physical sciences research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Plendl,Johannes N. ; Gielisse,Peter J. M.

Report Date : OCT 1969

Pagination or Media Count : 30

Abstract : The compressibility of solids is expressed in terms of fundamental physical quantities in relation to the energy of an electron in the L-shell orbital. When the concept of 'apparent valency' z sub a = (rho)z, the product of classical valency (z) and the ratio (rho) of the atomic coordinations of two successive polymorphs is used, the formula becomes generally applicable. As a result, the structure of each substance under ambient conditions can be classified as being either in the 'reduced,' 'basic' or 'elevated' state. This allows the prediction of volumetric compressibility data from pertinent atomic data and physical constants as well as a qualitative prediction of possible structural modifications. The relationship between the damping parameter of a solid and the radius ratio is shown to be useful in differentiating between the various possible structural modifications under a given set of pressure and temperature conditions. (Author)

Descriptors :   (*CRYSTAL STRUCTURE, CHEMICAL BONDS), (*SOLIDS, COMPRESSIVE PROPERTIES), MOLECULAR ASSOCIATION, HIGH PRESSURE, PHASE STUDIES, ATOMIC ORBITALS, TEMPERATURE

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE