Gamma-point lattice free energy estimates from O1 force calculations.
We present a new method for estimating the vibrational free energy of crystal (and molecular) structures employing only a single force calculation, for a particularly displaced configuration, in addition to the calculation of the ground state configuration. This displacement vector is the sum of the phonon eigenvectors obtained from a fast-relative to, e.g., density-functional theory (DFT)-Hessian calculation using interatomic potentials. These potentials are based here on effective charges obtained from a DFT calculation of the ground state electronic charge density but could also be based on other, e.g., empiric approaches.
Materials Research Department, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, 4000 Roskilde, Denmark. johannes.voss@risoe.dk
Johannes
J
Voss
Tejs
T
Vegge