Deviation from the Einstein Relation in Average Crystals Self-Diffusion of Ag+ Ions in α-Ag2S and α-Ag2Se

The mobility µ and the diffusion coefficient D of silver ions in Ag 2 S, Ag 2 Se and alloys Ag 2 S 1- x Se x have been measured by the aid of tracer technique using Ag 110m . The ratio µ/ D is found to deviate from the Einstein relation remarkably. Although such deviation is usually attributed to the existence of correlation between successive jumps of a diffusing ion, the present substances are so much disordered that the correlation effect theory cannot be applied. Recently Yokota has proposed a new model appropriate to our substances. The experimental results are compared with his theory with a minor modification. It is proved that the theory is applicable to our substances.