a A0*exp(-E0/(R_const*re.T)) Arrhenius expression A0 2.68e-17[1/s] Frequency factor E0 -243e3[J/mol] Activation energy k1 A1*exp(-E1/(R_const*re.T)) Rate constant A1 1e6[1/s] Frequency factor E1 60e3[J/mol] Activation energy k2 A2*exp(-E2/(R_const*re.T)) Rate constant A2 6.8e7[1/s] Frequency factor E2 85e3[J/mol] Activation energy S re.r_1/re.r_2 Selectivity parameter