P. Jana, G. K. Mallik, T. Ganguly
May 1, 1990
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Influential Citations
4
Citations
Journal
Journal of Luminescence
Abstract
Abstract The first excited singlet state of 2,2-diphenylethylamine (DPEA) shows a small exciton splitting of about 137 cm -1 . The measured lifetimes of the upper and lower excitonic levels are τ 1 and τ 2 , respectively, (τ 1 2 ) and only τ 2 is sensitive to polarity of solvents in which the spectrum of DPEA is measured. Flourescence emission mostly takes place from the lower level with longer lifetime which apparently indicates that the upper level is depopulated by rapid internal conversion. It is suggested that the geometry of DPEA, conformation of the NH 2 group, as also restricted orientation of the group, are not favourable for intramolecular CT interaction. Analysis of kinetic parameters of DPEA in different solvents in the presence of chloroalkanes at 77 K shows that it is lower excitonic level that is involved in CT complex formation with the heavy atom quenchers and that from this level the triplet excitation is enhanced.