The nonradiative transition rates follow the formula WNR = W (0) exp(-alphap), in which p is the amount of phonons matching the Power gap. The nonradiative transition premiums of Er3+ exhibit temperature dependence consistent with the multiphonon peace principle. In Tm3+ the temperature dependence of nonradiative relaxation premiums is intricate https://er-yb-yab-crystal63062.onesmablog.com/the-best-side-of-er-yb-yab-crystal-73718063