While DFT calculations indicate that the second step of path B (i.e., eq. 18, Ru(NH3)6 2+ + S2O8 2- ⇄ Ru(NH3)6 3+ + S2O8 3• -) has a larger activation energy (62 kJ/mol) than that for the reduction of S2O8 2-by CO2 • -(43 kJ/mol), the fact that eq 24 is essentially irreversible (Keq = 2.2 x 10 33 , Table ) and more facile than eq 16, forces the autocatalytic reaction to proceed through path B. As noted above, we find that the simulated voltammograms using just path B (shutting off path A) are identical to those computed using both A and B. Thus, we conclude that the direct reduction of S2O8 2-by CO2 • -, eq 16, does not significantly contribute to the overall S2O8 2-/C2O4 2-autocatalytic reaction on the time scale and conditions of the voltametric experiments reported herein.