Table 3. Parameters used in the K2-SURF model.

Parameter	Parameter description	Parameter value
α s,0,lim	Surface accommodation coefficient on an adsorbate-free surface	1
τ d,lim	Desorption lifetime of limonene on the surface	2.3 × 104 ns (Fig. 5), 2.6 × 104 ns (Fig. S2) a
k 1	First-order rate coefficient for the conversion of the C* down limonene configuration to the C* up limonene configuration	4.6 × 109 s–1 b
k 2	First-order rate coefficient for the conversion of the C* up limonene configuration to the C* down limonene configuration	6.8 × 108 s–1 c
σ lim	Effective adsorption cross-section of a limonene molecule	0.55 nm2 (Fig. 5), 0.79 nm2 (Fig. S2 and 6)
c 1	Fraction of limonene adsorbed as C* down, (1 – c1) is the fraction adsorbed as C* up	0.5

^aFor simplicity, the same value is assumed for the C* down and C* up configurations. Also note that these values are for room temperature (∼296 K). At other temperatures the following equation is used: (1/τ_d,lim) = exp(–6423 × (1/T) + 32.24).

^bThe activation energy associated with this rate coefficient is 24.6 kJ mol^–1 assuming a pre-exponential factor of 1 × 10¹⁴ s^–1.

^cThe activation energy associated with this rate coefficient is 29.3 kJ mol^–1 assuming a pre-exponential factor of 1 × 10¹⁴ s^–1.