The nonradiative changeover fees follow the components WNR = W (0) exp(-alphap), exactly where p is the volume of phonons matching the energy gap. The nonradiative changeover fees of Er3+ show temperature dependence consistent with the multiphonon rest idea. In Tm3+ the temperature dependence of nonradiative relaxation fees is complex https://elliotllkif.activablog.com/32333798/not-known-factual-statements-about-er-yb-yab-crystal