Accession Number : AD0633729

Title :   EXPERIMENTAL DETERMINATION OF THE ROLE OF SOLVENT-SOLVENT ENERGY MIGRATION IN SCINTILLATOR SOLUTIONS AND THE LIFETIME OF THE TRIPLET STATE OF LIQUID BENZENE.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Van Loben Sels,James Warren

Report Date : MAR 1966

Pagination or Media Count : 133

Abstract : Experimental quenching constants were obtained by the spectrophotofluorometric method in aerated and degassed solutions, using benzene, toluene, and p-xylene as donors, and using biacetyl as the acceptor. From the quenching constants and the known mean lifetimes of the excited donor states, experimental values for the energy transfer rate constants were determined. It was found that in the undiluted solvent systems, the solvent-solvent energy migration occurred at a rate comparable to that of the material diffusion, and that this rate decreased linearly with solvent dilution. The order of magnitude of the triplet state lifetime of liquid benzene was determined by measurements of the phosphorescence to fluorescence ratio for biacetyl in degassed benzene solution. Comparison of the value for this ratio determined for direct acceptor excitation with the value found for the benzene sensitized acceptor excitation, resulted in the detection of the benzene triplet state and the calculation of its approximate lifetime. This lifetime was found to be of the order of 10 to the -8th power seconds. (Author)

Descriptors :   (*SCINTILLATION COUNTERS, LIQUIDS), (*SOLVENTS, *LUMINESCENCE), (*BENZENE, MOLECULAR ENERGY LEVELS), TOLUENES, XYLENES, EXCITATION, ENERGY, QUENCHING(INHIBITION), TRANSPORT PROPERTIES, DIFFUSION, PHOSPHORESCENCE, SPECTROPHOTOMETERS

Subject Categories : Radiation and Nuclear Chemistry
      Nuclear Instrumentation
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE