Optimizing the Full Potential Linear Muffin Tin Orbital Basis Set

Density functional theory (DFT) calculations for 5f and 5d block materials and materials in high compression require the use of all-electron methods that explicitly treat core electrons. The full potential linear muffin-tin orbital (FP-LMTO) method is one of the most efficient all-electron approaches. Its efficiency comes from a basis set that is built to be close to the true solutions, so that in principle only a small number of basis functions are needed for an accurate calculation. However, the accuracy of the method relies on a judicious choice of so-called "tail energies" and other muffin-tin parameters in constructing this basis, and currently there is no procedural way to determine them. Since these parameters satisfy a variational principle, they can be chosen to optimize the accuracy of calculations. We investigate better ways to choose these parameters, including physics-informed choices. We also explore alternative basis set constructions motivated by the LMTO method.