2016/09/30 by Christopher J. Stein, Markus Reiher · 2 citations
Physics and Astronomy · #physics.chem-ph #cond-mat.str-el #physics.comp-ph #quant-ph
paper · pdf · doi:10.1080/00268976.2017.1288934
published as Mol. Phys. 115 (2017) 2110-2119 · 8 pages, 2 figure, 3 tables
arxiv created 2016/11/16 · arxiv updated 2020/02/18
One of the most critical tasks at the very beginning of a quantum chemical investigation is the choice of either a multi- or single-configurational method. Naturally, many proposals exist to define a suitable diagnostic of the multi-configurational character for various types of wave functions in order to assist this crucial decision. Here, we present a new orbital-entanglement based multi-configurational diagnostic termed Zs(1). The correspondence of orbital entanglement and static (or nondynamic) electron correlation permits the definition of such a diagnostic. We chose our diagnostic to meet important requirements such as well-defined limits for pure single-configurational and multi-configurational wave functions. The Zs(1) diagnostic can be evaluated from a partially converged, but qualitatively correct, and therefore inexpensive density matrix renormalization group wave function as in our recently presented automated active orbital selection protocol. Its robustness and the fact that it can be evaluated at low cost make this diagnostic a practical tool for routine applications.