Globally-Optimized Local Pseudopotentials for (Orbital-Free) Density Functional Theory Simulations of Liquids and Solids

Orbital-free density functional theory (OFDFT) is a promising technique for accurate, large-scale, quantum simulations. One key element determining the fidelity of OFDFT is the need to use local pseudopotentials (LPSs) to describe electron-ion interactions. We developed a global optimization strategy for LPSs that enables OFDFT to reproduce solid and liquid properties obtained from Kohn-Sham DFT, resulting in globally optimized LPSs (goLPSs) that can be used in solid- and/or liquid-phase simulations, depending on the fitting process.¹ Moreover, we can improve the initial transferability of goLPSs by fitting to the delta-gauge² and the valence electron density in the solid phases. A variety of test cases show that we can (1) improve solid properties compared to our previous bulk-derived LPS generation scheme; (2) refine predicted liquid and solid properties, as well as phase transition temperatures, by adding force-matching data; and (3) generate accurate goLPSs directly from the local channel of non-local pseudopotentials. We also will introduce the new goLPS library available.
¹ B. G. Del Rio et al., J. Chem. Theory Comput. 13, 3684 (2017).
² K. Lejaeghere et al., Science 351, 6280 (2016).