Anomalous Emission of C-Nitroso Compounds

Abstract

Abstract There is a clear need for experimental studies specifically designed to detect fluorescence or phosphorescence from excited states higher than S1 or T1, since they provide a means of evaluation of rate parameters of internal conversion in polyatomic molecules. Although various theoretical approaches1 have been made to the study of radiationless transitions, our present understanding of these processes remains imcomplete due to absence of sufficient experimental data. The wellknown azulene emission, the first authentic exception to Kasha rule was discovered as early as in 19552. This was followed by observation of similar anomalous emission from many derivatives of azulene3,4,5. Besides this, a number of workers have reported anomalous emissions from higher excited states in other molecules1,6,7. Many of these reported anomalous emissions were later proved to be as due to impurities and in some cases as arising from higher vibronic levels of the S1 state. Most of the remaining cases are rendered l...