Accession Number : AD0478238


Title :   TRIPLET STATE ZERO FIELD SPLITTINGS OF SOME STRUCTURALLY RELATED AROMATIC HYDROCARBON AND HETEROCYCLIC MOLECULES,


Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS


Personal Author(s) : Siegel ,Seymour ; Judeikis,Henry S


Report Date : Jan 1966


Pagination or Media Count : 14


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)


Descriptors :   *PARAMAGNETIC RESONANCE , *MOLECULES , *AROMATIC COMPOUNDS , *HETEROCYCLIC COMPOUNDS , MOLECULAR SPECTROSCOPY , MOLECULAR SPECTROSCOPY , PHOSPHORESCENCE , SPECTRUM ANALYZERS , POLARIZATION , ETHYL ETHERS , ISOTROPISM , EMISSIVITY , ULTRAVIOLET SPECTRA , VISIBLE SPECTRA


Subject Categories : Atomic and Molecular Physics and Spectroscopy


Distribution Statement : APPROVED FOR PUBLIC RELEASE