Efficient Free-energy Calculation of Proton Transfer by Constrained Density Functional Theory and Geometrically Restrained Molecular Dynamics Simulation

Recently, we proposed an MD simulation scheme for free-energy calculations of proton transfers that employs the constrained DFT method and the energy-gap coordinate. The present paper proposes to streamline the free-energy calculations by using adiabatic MD trajectories and umbrella sampling with geometric coordinates. The calculated free-energy profile reproduces the more accurate results by the free-energy perturbation.