TRIPLET STATE ZERO FIELD SPLITTINGS OF SOME STRUCTURALLY RELATED AROMATIC HYDROCARBON AND HETEROCYCLIC MOLECULES,
Abstract
The triplet state zero field splitting parameters D and E have been determined from the delta m = plus or minus 1 EPR spectra of the photo-excited triplet states of several structurally related aromatic hydrocarbons and aromatic heterocyclic molecules, using diethyl ether glasses at 77 K. The values of the splitting parameters per cm for the various molecules are as follows: biphenyl D = 0.1092, E = 0.0036; fluorene D = 0.1075, E = 0.0033; carbazole D = 0.1022, E = 0.0066; dibenzofuran D = 0.1071, E = 0.0092; dibenzothiophen D = 0.1130, E = 0.0021. The uncertainties in these numbers are plus or minus 0.2 Mk for D and plus or minus 0.1 Mk for E. Lifetimes of the triplet states were also determined. A discussion of the results in terms of conjugation of the hetero atom with the aromatic rings is given. The results are compared to the published values of D and E for phenanthrene. It is found that biphenyl is a better hydrocarbon model than phenanthrene for the heterocyclics investigated in this report. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1966
- Accession Number
- AD0478238
Entities
People
- Henry S. Judeikis
- Seymour Siegel
Organizations
- The Aerospace Corporation