INFLUENCE OF TYPE AND CONCENTRATION OF EXTERNAL HEAVY-ATOMS UPON PHOSPHORESCENCE LIFETIMES

The phosphorescence lifetimes and spectra are given of phenanthrene, carbazole, quinine, 7,8-benzoflavone, and thiopropazate at 77 K in 10/90 v/v ethanol/water with different heavy atom concentrations of iodide (KI), silver (AgNO3), and thallous (TINO3). Both short (millisecond) and long (second) decaying components are measured as a function of heavy atom concentration. In all cases studied, silver ion had a larger effect on the phosphorescence lifetime than iodide which indicates a “charge transfer complex” heavy atom effect is a more likely mechanism than an “exchange” heavy atom effect. Thallous ion has relatively little effect on the low temperature lifetimes and spectra which is opposite to its effect for room temperature phosphorimetry. © 1979, American Chemical Society. All rights reserved.