title: Communication: Extension of a universal explicit electron correlation correction to general complete active spaces.
abstract: We present the extension of a recently proposed universal explicit electron correlation (F12) correction for multi-reference perturbation theories to general complete active spaces and arbitrary choices of complete active space self-consistent field (CASSCF) orbitals. This F12 correction is applied to Mukherjee's multi-reference second-order perturbation theory (Mk-MRPT2). Pilot examples show the expected reduction of the basis sets incompleteness error of about two cardinal numbers.
authors.affiliation: Karlsruhe Institute of Technology, Institute of Physical Chemistry, Theoretical Chemistry Group, KIT Campus South, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany. haunschild@kit.edu
authors.forename: Robin
authors.initials: R
authors.lastname: Haunschild
authors.forename: Lan
authors.initials: L
authors.lastname: Cheng
authors.forename: Debashis
authors.initials: D
authors.lastname: Mukherjee
authors.forename: Wim
authors.initials: W
authors.lastname: Klopper