Gibbs free energy of activation (ΔG^≠, kcal mol⁻¹), diffusion rate constant (k_D, M⁻¹ s⁻¹), TST thermal rate constant (k_T, M⁻¹ s⁻¹), Eckart-tunneling-corrected rate constants (k_eck, M⁻¹ s⁻¹), diffusion-corrected apparent rate constants (k_app, M⁻¹ s⁻¹) and branching ratio Γ (%) at 298.15 K for the FHT, RAF and SET reactions of the rosmarinate mono-anion (RA⁻) with HOO˙ radicals in water calculated at the M05-2X/6-311++G(2df,2p) level of theory. The values in parentheses correspond to the results obtained in the PEA phase.

Position	ΔG≠	k D	k T	k eck	k app	Γ
FHT
O3H	18.6 (17.1)	2.41 × 109 (2.55 × 109)	4.73 × 102 (8.25 × 103)	6.44 × 104 (1.39 × 105)	4.73 × 102 (8.25 × 103)	25.70
O4H	18.8	2.41 × 109	3.44 × 102	4.26 × 104	3.44 × 102	18.67
O7H	18.8 (17.6)	2.39 × 109 (2.53 × 109)	8.73 × 102 (7.05 × 103)	2.72 × 105 (2.58 × 105)	8.73 × 102 (7.05 × 103)	47.41
O8H	20.2	2.40 × 109	1.51 × 102	8.44 × 104	1.51 × 102	8.21
RAF
C20	21.4 (23.8)	1.98 × 109 (2.10 × 109)	9.76 × 10−2 (8.01 × 10−3)	1.36 × 10−1 (1.12 × 10−2)	9.76 × 10−2 (8.01 × 10−3)	0.01
C21	23.7	1.95 × 109	2.65 × 10−3	4.42 × 10−3	2.65 × 10−3	0.00
SET
	36.1 (103.1)	8.36 × 109 (8.93 × 109)	5.03 × 10−13 (4.10 × 10−62)	—	5.03 × 10−13 (4.41 × 10−62)	0.00