DETERMINATION OF THE MEAN LIFE OF THE FIRST EXCITED STATE OF SOME COMPLEX AROMATIC COMPOUNDS IN AERATED SOLUTION AND THE ABSOLUTE QUANTUM YIELD OF FLUORESCENCE OF BIACETYLIN SOLUTION

摘要

The transfer of electronic excitation energy from the lowest excited singlet state of naphthalene benzene and twelve of its alkyl derivatives to the lowest excited singlet state of biacetyl tesafcoen. studied in aerated hexane solutions at 28RC by the spectrophotofluorometric method. Stern-Volmer diagrams were drawn to show the donor quenching by the acceptor under conditions of low optical density. Slopes obtained-from these curves are independent of donor concentration and equal tonwhere k is the specific rate constant for the transfer process and is the lifetime of the donor's singlet state in aerated solutions. A value for is obtained if it is assumed that the coalitional transfer efficiency is unity and that the specific rate constant can be calculated by use of the Debye equation. Lifetimes obtained in this manner agree with those measured directly by Ivan ova for the same donors after the latter's work has been corrected for self-quenching.nThe absolute quantum yield of fluorescence of anthracite in ethanol luau tKitttt calculated by a comparison of its fluorescence spectrum with mat of the quinine bisulfate standard; the experimental result agrees with the published literature values. With the same method the quant turn yield of biacetyl in three different aerated solutions is found at room temperature.