Relative efficiencies of triplet-triplet energy transfer from benzene (3B1u) to monoolefins and 1,3-butadiene

Relative efficiencies of quenching of the benzene triplet ( 3 B 1u ) in the gas phase by a number of monoolefins, 1,3-butadiene, and several inorganic gases (SF 6 , Xe, CO 2 , N 2 O) have been determined by a competitive technique. Most of the data have been obtained at room temperature (~26 °C) and some measurements have been made at 30 and 70 °C. The latter indicate that the efficiency of the energy transfer to the monoolefins and 1,3-butadiene increases with increasing temperature. The mechanism of the "energy transfer" to the olefins appears to involve a chemical interaction with the benzene ( 3 B 1u ) molecules. The inert gases are inefficient quenchers.The kinetic data obtained with 1,3-butadiene indicate that this diolefin quenches also to an appreciable extent the first excited singlet of benzene ( 1 B 2u ). This has been confirmed by direct fluorescence measurements.