Interactions between rare earth ions in the ethyl sulphates

摘要: The existing data on the interactions between a large number of different pairs rare earth ions in ethyl sulphates is surveyed as whole, and some comparisons are made with similar for LaCl3 LaBr3. Such an analysis all enables one to draw much firmer conclusions about interaction mechanisms than discussion results any particular pair ions. It shown that exchange contributes very little interaction, electric multipole-multipole contributions negligible. This suggests sizeable nondipolar contribution should be attributed virtual phonon (VPE). Estimates this based upon standard theories show must enhanced by factor 40-50 order agree experimental measurements. That enhancement remarkably consistent data, can invent plausible model account terms from optical modes, indicates VPE appropriate mechanism.