Actinometric determination of absolute fluorescence quantum yields

Abstract

The absolute fluorescence quantum yield of 9,10-diphenylanthracene in deaerated cyclohexane, the value of which has long been a matter of controversy, has been determined by use of a new method based on chemical actinometry. This technique avoids many of the intrinsic error sources of the other absolute methods. The sample's emission intensity is measured by almost completely surrounding the sample with an actinometer solution, and the excitation intensity is directly measured with the same type of actinometer. The measured sample emission intensity is corrected for the fraction of exciting light which is not absorbed within the sample solution and the fraction of fluorescence which escapes through the entrance and exit ports of the excitation beam. The absolute fluorescence yield is the ratio of the "corrected" sample intensity to the excitation intensity. The value we obtain with this method for 9,10-diphenylanthracene in cyclohexane is 0.90 to within 4%.completely with an actinometer solution, measures the (1)

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