Libxc: A library of exchange and correlation functionals for density functional theory

Abstract

The central quantity of density functional theory is the so-called exchange-correlation functional. This quantity encompasses all non-trivial many-body effects of the ground-state and has to be approximated in any practical application of the theory. For the past 50 years, hundreds of such approximations have appeared, with many successfully persisting in the electronic structure community and literature. Here, we present a library that contains routines to evaluate many of these functionals (around 180) and their derivatives.

ERKALE—A flexible program package for X‐ray properties of atoms and molecules

“…[47] The atom-centric radial integrals in the Becke scheme are computed using Gauss-Chebyshev quadrature of the second kind. [63] The angular integrals on each radial shell are performed by default with Lebedev quadrature, [65][66][67][68][69][70] but Lobatto quadrature [71] is available as well.…”

“…The program shares substantial amounts of code with, for example, PSI3, MPQC, and CP2K through its use of the libint library [46] for the computation of two-electron integrals, and on the other hand with ABINIT, BigDFT, and GPAW through the use of the libxc library [47] for evaluating exchange-correlation (XC) energy densities and their functional derivatives in DFT calculations. The program is freely available under the terms of the GNU General Public License [48] ‡ .…”

molgw 1: Many-body perturbation theory software for atoms, molecules, and clusters

“…molgw's reliance on several external libraries eases the code's maintenance. 2-, 3-, and 4-center Coulomb integrals are all obtained from the library libint [59], while the exchange-correlation energy density, potential, and kernel are calculated with the library libxc [62]. molgw is parallelized using Message Passing Interface (MPI) for the communications and ScaLAPACK for the linear algebra.…”

Accurate Reference Data for the Nonadditive, Noninteracting Kinetic Energy in Covalent Bonds

“…The azimuthal cooridinate is solved analytically, while the prolate spheroidal problem is solved numerically on a 5329 point grid. We evaluate approximate exchange correlation and kinetic energy functionals using the Libxc library [22].…”