XCFun

Description:
XCFun is a library of approximate exchange-correlation functionals
Website:
https://github.com/dftlibs/xcfun
License:

A modified LGPL license that allows SCM to link statically with XCFun

The XCFun library is licensed under the LGPL license. This means that you may modify and distribute the library freely as long as you also release any changes made by you under the LGPL license. If you are just making modifications without distributing the modified library you are not obliged to release your changes. However, we do of course welcome all contributions as long as they are well tested and thought out

Reference:
Ulf Ekström, Lucas Visscher, Radovan Bast, Andreas J. Thorvaldsen and Kenneth Ruud, Arbitrary-Order Density Functional Response Theory from Automatic Differentiation, Journal of Chemical Theory and Computation 6, 1971 (2010), DOI: 10.1021/ct100117s