Monte Carlo evaluation of the equilibrium isotope effects using the Takahashi–Imada factorization of the Feynman path integral

摘要: Abstract The Feynman path integral approach for computing equilibrium isotope effects and fractionation corrects the approximations made in standard methods, although at significantly increased computational cost. We describe an accelerated based on three ingredients: fourth-order Takahashi–Imada factorization of integral, thermodynamic integration with respect to mass, centroid virial estimators relevant free energy derivatives. While first ingredient speeds up convergence quantum limit, second third improve statistical convergence. combined method is applied compute constants exchange reactions H 2 + D ⇌ HD .