Streak camera measurements of the relative yield of the excited state of cyclohexane (CH*) as a function of electron scavenger concentration (perfluoro-n-hexane, CO/sub 2/, and N/sub 2/O) strongly indicate that less than 10% of the CH* is formed by direct excitation. The effects of the scavenging of geminate electrons on the yield of CH*, in terms of the formulation f/sub s/ = (..cap alpha..(S))/sup n//(1 + (..cap alpha..(S))/sup n/), where f/sub s/ is the fraction of geminate electrons scavenged, (S) is the scavenger concentration, and ..cap alpha.. and n are constants (parameters), can be described as follows: for perfluoro-n-hexane, n = 1 and ..cap alpha.. = 35 M/sup -1/; for CO/sub 2/, n = 0.6 and ..cap alpha.. = 50 M/sup -1/; for N/sub 2/O, n = 0.6 and ..cap alpha.. = 40 M/sup -1/. The effects of static quenching of CH* by the electron scavenger are taken into account in the analysis and are estimated from the values measured for the quenching rate constants. They obtain quenching rate constants, corrected for the effects of time-dependent rates, 2.4 x 10/sup 10/ M/sup -1/ s/sup -1/ for N/sub 2/O and CO/sub 2/ (/plus minus/20% estimated uncertainty) and 0.71 x 10/sup 10/more » M/sup -1/ s/sup -1/ for perfluoro-n-hexane (/plus minus/15% estimated uncertainty).« less