Spectral properties and kinetics of cationic transients generated in electron-pulse-irradiated alkanes

After electron-pulse irradiation of liquid cyclohexane and methylcyclohexane containing carbon tetrachloride as an electron scavenger, transient optical absorption bands were observed with peak wavelengths of about 500 nm. The bands are assigned to the corresponding alkane radical cations. Solute cation formation was studied in cyclohexane using solutes asn-decane,n-dodecane,n-hexadecane and benzene. It is shown that the solutes undergo electron transfer to cyclohexane radical cations. Charge-transfer rate constants were estimated and their observed correlation with the difference of the liquid-phase ionization potentials of solvent and solute, ΔE =I¹_C6H12 -I¹_S, is qualitatively compared with electron transfer theories.