A method proposed by Garlick and Gibson is often applied to determine the energy positions of traps in phosphors. A critical analysis of Garlick and Gibson’s method based on a mathematical determination of the applicable temperature range and on experimental evidence shows that the trap depths obtained are lower than those found by other methods. Especially the frequency-of-escape constants calculated subsequently contrast strongly to those determined by separate measurements.
C. H. HAAKE, "Critical Comment on a Method for Determining Electron Trap Depths," J. Opt. Soc. Am. 47, 649-652 (1957)