DEBYE WALLER FACTORS AND DEBYE TEMPERATURES : for research scholars

The Debye-Waller factors and Debye temperatures of crystals are parameters of lattice dynamical interest. The experimental determination of these parameters by the X-ray diffraction technique is the objective of an on-going programme in this laboratory. So far the Debye-Waller factors and Debye temperatures have been determined for a large number of materials having different crystal structures. A systematic study on the effect of lattice strain on the Debye-Waller factors of strained silver powders constitutes the theme of this dissertation. Strain is produced in silver by repeated grinding. After each spell of grinding the X-ray diffractogram is recorded. The lattice strain and Debye-Waller factors are determined from the half widths and integrated intensities of the Bragg reflections respectively. From the Debye-Waller factors the Debye temperatures of strained silver powders have been determined. From a relation between X-ray Debye temperature and the vacancy formation energy the vacancy formation energy of silver as a function of lattice strain has been determined.