title: Entanglement Measures for Single- and Multireference Correlation Effects.
abstract: Electron correlation effects are essential for an accurate ab initio description of molecules. A quantitative a priori knowledge of the single- or multireference nature of electronic structures as well as of the dominant contributions to the correlation energy can facilitate the decision regarding the optimum quantum chemical method of choice. We propose concepts from quantum information theory as orbital entanglement measures that allow us to evaluate the single- and multireference character of any molecular structure in a given orbital basis set. By studying these measures we can detect possible artifacts of small active spaces.
authors: †ETH Zurich, Laboratory of Physical Chemistry, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland.
authors: Katharina
authors: K
authors: Boguslawski
authors: †ETH Zurich, Laboratory of Physical Chemistry, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland.
authors: Pawel̷
authors: P
authors: Tecmer
authors: ‡MTA-WRCP Strongly Correlated Systems "Lendület" Research Group, H-1525, Budapest, Hungary.
authors: Örs
authors: Ö
authors: Legeza
authors: †ETH Zurich, Laboratory of Physical Chemistry, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland.
authors: Markus
authors: M
authors: Reiher
keywords: DMRG; correlation effects; entanglement; transition metals; von Neumann entropy