E.3 Libxc

Libxc is, accordingly to its website, “a library of exchange-correlation functionals for density-functional theory. The aim is to provide a portable, well tested and reliable set of exchange and correlation functionals that can be used by all the ETSF codes and also other codes.” More information may be found at https://libxc.gitlab.io. The version distributed with the FHI-aims source code is 6.1.0.

Compiling FHI-aims with Libxc provides opportunity to perform SCF calculations with either the internal FHI-aims routines or the large repository of options available in Libxc. Libxc support is beneficial for extended functionality in FHI-aims, such as calculations of NMR parameters and the atom_sphere radial solver. If a particular method requested by the user requires Libxc, the calculation will stop and inform the user to re-compile with Libxc support. Most users running standard DFT/hybrid SCF calculations will not need to compile with Libxc support.

Prerequisites:

Libxc is written in C and therefore needs a C compiler with appropriate options in addition to the usual Fortran compiler with which FHI-aims is built.

Specifically for Libxc, include in Makefile or make.sys: