X-Ray Diffraction Study of Fine Gold Particles Prepared by Gas Evaporation Technique. II. Characteristic Temperature

Abstract

From an analysis of the X-ray Debye-Scherrer lines from fine gold particles with the mean size of 100 A, the mean square atomic displacement, < u 2 >, was determined at several temperatures in a range from 112 to 298 K. The temperature dependence of < u 2 > was analysed on the basis of the Einstein approximation for the thermal vibrations of atoms and a characteristic temperature θ M =143±3 K was obtained. This is 15% less than the Debye temperature θ M =168 K for the bulk crystal. It was found that the observed < u 2 > includes the temperature independent component, impling the existence of some kind of static lattice distortions. The contribution from such lattice distortions depends on the preparation condition of fine gold particles.