The formation and reactions of radical anions in n-hexane at 190 K wer
e investigated by pulse radiolysis and time-resolved fluorescence-dete
cted magnetic resonance (FDMR). Electron attachment was found to occur
for compounds with gas-phase electron affinities (EA) more positive t
han - 1.1 +/- 0.1 eV. The FDMR concentration and time dependence are i
nterpreted as evidence for self-exchange electron-transfer reactions,
indicating that formation of dimer radical anions is not prevalent for
the range of molecules studied. FDMR detection of radical anions is m
ainly restricted to electron accepters with EA less than approximately
0.5 eV.