Understanding Luminescence Spectra and Efficiency Using Wp and Related Functions

This book gives a semiquantitative understanding of the properties observed in luminescence, i.e., where energy absorption and emission occur, and with what efficiency these conversion processes take place. The authors give a correct treatment of the offset dependence and the temperature dependence of nonradiative rates. The Wp function is defined as the sum of thermally weighted Franck-Condon factors. It is obtained in one dimension in several forms, and a useful recursion relation is derived between Wp's with nearby p indices. Two classes of applications are considered. First, an exposition of the broad classes of luminescence behavior is given and the Wp function and related functions are applied to each. Then the detailed application of these functions to specific experimental data, namely, to Eu3+, Tm3+, and Yb3+ in oxysulfides and oxychlorides and to Cr3+ in ruby is extensively discussed. The authors give a thorough review of the related literature. The many exact and approximate forms, some with certain errors, for Wp and related functions are listed and their relationship to Wp are given.