Accession Number:

AD0271421

Title:

X-RAY DIFFRACTION STUDIES OF THERMAL MOTIONS IN CRYSTALS

Descriptive Note:

Corporate Author:

GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION

Personal Author(s):

Report Date:

1961-05-31

Pagination or Media Count:

1.0

Abstract:

Research continued on the general study, primarily by x-ray intensity-vs-temperature I vs T measurements, of thermal motions in crystals and their interaction with other phenomena of interest in crystal physics. Critical re-exa ination of experimental techniques led to a better understanding of background intensities and subsequently to the solution of several persistent problems. A graphical method curvature method developed for comparing the temperature dependence of the normalized temperature slope of log I vs T, AT, with the theoretical prediction, fx, by means of log-log plots. Results indicate that the curvature method is sensitive to discrepancies between experimental observations and theory, and that the Debye-Waller theory does not adequately describe the temperature dependence of Bragg intensities for AgCl. Thermal expansion data for AgCl, NaCl, and Al in the 100 K to 300 K temperature range were obtained. The discrepancies found between theory and experiment indicate a breakdown in the simplified MieGruneisen thermal expansion theory used, or the Debye lattice vibration theory, or both, for AgCl. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE