CONTRIBUTION OF EXCITED-STATES IN THE HEAVY-ION RADIOLYSIS OF CYCLOOCTANE

The yields of the major end products produced in cyclooctane have been used to probe the effects of the track structure on radiation chemica l processes induced by gamma-rays, 1-15 MeV protons (LET 50-10 eV/nm), 5-20 MeV helium ions (LET 150-70 eV/nm), 7-29 MeV carbon ions (LET 80 0-660 eV/nm) and 10 MeV oxygen ions (LET 1150 eV/nm). There is a gradu al decrease in the yields of cyclooctene, bicyclooctyl, and bicyclo[3. 3.0]octane (pentalane) with increasing LET and there appears to be a c onsiderable change in the yields of individual primary decomposition c hannels with varying LET. Shifting from gamma-radiolysis to proton rad iolysis results in an increase in product formation through the triple t state with a concomitant decrease in the singlet excited state, prob ably due to the enhanced probability of cross combination reactions of electrons and cations in the high density region of heavy particle tr acks. It appears that the yield of both the triplet and singlet excite d states of cyclooctane slowly decrease with increasing LET.