LASER FLASH-PHOTOLYSIS STUDIES ON THE INDUCED-QUENCHING PROCESS COMPETING WITH HYDROGEN-ATOM ABSTRACTION OF TRIPLET BENZOPHENONE - HEAVY-ATOM EFFECT

The rate constants (k(HA) and k(IQ)) for the hydrogen atom abstraction (HA) and induced-quenching (IQ) processes between tripler benzophenon e ((BP)-B-3) and halogenated toluenes (XTL) were determined by means of nanosecond laser flash photolysis techniques. It was found that the k(IQ) value increased proportionally with increasing the squared summ ation of the spin-orbit coupling constant (zeta) of atoms involved in XTL while the k(HA)'s were almost indifferent. it was demonstrated tha t the IQ process was the intersystem crossing process which was induce d mainly by the spin-orbit interaction between (BP)-B-3 and XTL.