Diabat Interpolation for Polymorph Free-Energy Differences

K Kamat and B Peters, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 8, 655-660 (2017).

DOI: 10.1021/acs.jpclett.6b02795

Existing methods to compute free-energy differences between polymorphs use harmonic approximations, advanced non-Boltzmann bias sampling techniques, and/or multistage free-energy perturbations. This work demonstrates how Bennett's diabat interpolation method (J. Comput. Phys. 1976, 22, 245) can be combined with energy gaps from lattice-switch Monte Carlo techniques (Phys. Rev. E 2000, 61, 906) to swiftly estimate polymorph free-energy differences. The new method requires only two unbiased molecular dynamics simulations, one for each polymorph. To illustrate the new method, we compute the free-energy difference between face-centered cubic and body-centered cubic polymorphs for a Gaussian core solid. We discuss the justification for parabolic models of the free-energy diabats and similarities to methods that have been used in studies of electron transfer.

Return to Publications page