Table 1.

Potential energy, enthalpy, and free energy changes and intrinsic barriers (in kcal/mol) involved in hydrogen atom abstraction from methane by models in Figure 11

Systems	ΔE; ΔH; ΔG	ΔE‡; ΔH‡; ΔG‡	$\Delta E_{int}^{‡}$; $\Delta H_{int}^{‡}$; $\Delta G_{int}^{‡}$
Fe(IV)=O	17.1; 14.7; 14.3	25.1; 20.1; 22.1	15.3; 11.6; 14.0
HO-Fe(IV)-μO-Fe(IV)=O	10.8; 7.2; 10.4	24.8; 19.7; 25.0	19.0; 15.9; 19.4
HO-Fe(IV)-μO-Fe(IV)-OH	0.7; −0.3; −2.1	19.8; 14.8; 15.4	19.4; 14.9; 16.4
Fe(IV)-(μO)2-Fe(IV)-OH**	3.6; 2.1; −1.0	15.7; 11.2; 12.4	13.9; 10.1; 12.9

^*ΔG values are calculated at 5 °C.

^**ΔG and

^‡ΔG values for Fe(IV)-(μO)₂-Fe(IV)-OH₂ are 3.1 and 11.1 kcal/mol.