Measurements of primary radical concentrations generated by pulsed laser photolysis using fluorescence detection

Abstract

Details of a novel technique for direct real-time measurement of the primary radical concentrations generated in pulsed laser photolysis (PLP) experiments are presented. The method takes advantage of the large increase in fluorescence quantum yield that occurs when a nitroxide containing a suitable fluorophore couples with a carbon-centered radical. The technique is applied to PLP experiments which involve photolysis of azobisisobutyronitrile (AIBN) or azobis(methyl isobutyrate) (AIBMe) in the presence of 4-(1-naphthoyloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl (NTEMPO). In these experiments, the method is shown to be capable of reliably measuring transient radical concentrations of less than..