aV3 max(cV3/1[mol/l],eps) V(3+) activity aV2 max(cV2/1[mol/l],eps) V(2+) activity aH max(cH_neg/1[mol/l],eps) H(+) activity aHSO4 max(cHSO4_neg/1[mol/l],eps) HSO4(-) activity aSO4 max(cSO4_neg/1[mol/l],eps) SO4(2-) activity Eeq_neg Nernst(E0_neg,T,aV3/aV2) Equilibrium potential i0_neg F_const*k_neg*aV2^(1-alpha_neg)*aV3^alpha_neg*1[mol/l] Exchange current density rd kd*((aH-aHSO4)/(aH+aHSO4)-beta) Dissociation rate phil phil_neg Electrolyte potential (for postprocessing) phis phis_neg Electrode potential (for postprocessing)