Fig. 4.

Correlation of observed KIEs with calculated r₀ values as a function of pressure. (A) The calculated KIE dependence on r₀ from Eqs. 4 and 5 (shown in Fig. 3) when ΔΔH^‡ is fixed to 5.2 kJ·mol⁻¹. (B) The measured KIE versus p at 25°C. The solid line is a fit to KIE = k_0,H/k_0,D exp(−ΔΔV^‡p/R_pT). The increase in observed KIE is consistent with a decrease in the equilibrium separation, r₀, from ≈1.7 Å to ≈1.0 Å (depicted by the arrow).