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ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS Received 11 November 1974
4.
DEFECT INTERACTIONS IN INTRINSIC SILVER CHLORIDE A.R. Allnatt, Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7; J. Corish, Department of Chemistry, University College, Dublin, Ireland and P.W.M. Jacobs, Physics and Chemistry of Solids, Cavendish Laboratory, Cambridge, England.
that coexist with defect clusters. As a consequence of a “site-blocking” effect,the mobility of “free mobile vacancies” and the apparent correlation factor for cation tracer diffusion decrease with an increase in deviation from stoichiometry.
6.
Approximate formulae are developed for the activity coefficients of vacancies and interstitials in intrinsic silver chloride. The numerical values are compared with the Debye—Huckel approximation and the useful range of the formulae is discussed. Received 29 October 1974 Revised 13 January 1975
5.
EFFECT OF THE DEVIATION FROM STOICHIOMETRY ON CATION SELFDIFFUSION AND ISOTOPE EFFECT IN WIJSTITE, Fe1..~O W,K. Chen and N.L. Peterson, Materials Science Division, Argonne National Laboratory, Argonne, III. 60439 U.S.A.
Diffusion of ~ Fe in Fe1 ~0 crystals has been measured by a serial-sectioning technique as a function of temperature and deviation from stoichiometry. The results indicate that the diffusivity increases slightly at 1200°C, decreases at 802°C with an increase in X, and is insensitive to change in x at 1003°C. The ternperature dependence of the cation diffusivity in Fe0~Ois given by the expression,D = in (8.6 0.5) X 2/sec, the±ternl0-~exp range (—29350 ±300/RI) cm isotope effect for perature 700—1340°C.The cation self-diffusion was measured by simultaneous diffusion of 52Fe and 59Fe in Fe 1.~Oat various temperatures and values of x. Although the measured values offiSK are independent of temperature within the limits of experimental error, they decrease with an increase in the deviation from stoichiometry. The experimental results appeared to be consistent with the diffusion of Fe ionsvia “free mobile vacancies”
Vol. 17, No. I
CHARACTERISTIC ELECTRON ENERGY LOSSES IN GERMANIUM L.C. Speller, Department of Physics, District of Columbia Teachers College, Washington, D.C. 20001, U.S.A., and Department ofPhysics and Astronomy, Howard University, Washington, D.C. 20059, U.S.A. and H. Mendlowitz, Department of Physics and Astronomy, Howard University, Washington, D.C. 20059, U.S.A. and National Bureau of Standards, Washington, D.C. 20234, U.S.A.
The characteristic electron energy loss spectrum of germanium was studied in a transmission type experiment as a function of the changes in structure due to electron bombardment. The structure of the material was characterized by electron micrograph and diffraction techniques. The electron energy loss spectrum of germanium was studied up to 45 eV, and loss peaks were observed at 15.7 and 31.6eV as well as a 6 eV carbon loss. The positions of the most intense characteristic energy loss peak at 15.7 eV and its first multiple were constant for a large variation in the lattice parameters for the individual films. Received 5 June 1974 Revised 3 February 1975
7.
PRESSURE AND TEMPERATURE DEPENDENCES OF THE DIELECTRIC CONSTANT, RAMAN SPECTRA AND LATTICE CONSTANT OF SnI4 P.S. Peercy, G.A. Samara and B. Morosin, Sandia Laboratories, Albuquerque, New Mexico 87115, U.S.A.
The pressure and temperature dependences of the Raman frequencies, static dielectric constant of the molecular crystal Sn!4 were investigated. These results are combined to evaluate the pure volume and pure temperature (i.e. volume-independent) dependences