Title

Projector-Based Quantum Embedding for Molecular Systems: An Investigation of Three Partitioning Approaches

Publication Date

7-14-2021

Department

Ames Laboratory; Chemistry

Campus Units

Ames Laboratory, Chemistry

OSTI ID+

1810409

Report Number

IS-J 10561

DOI

10.1021/acs.jpca.1c03821

Journal Title

Journal of Physical Chemistry A

Volume Number

125

Issue Number

29

First Page

6384

Last Page

6393

Abstract

Projector-based embedding is a relatively recent addition to the collection of methods that seek to utilize chemical locality to provide improved computational efficiency. This work considers the interactions between the different proposed procedures for this method and their effects on the accuracy of the results. The interplay between the embedded background, projector type, partitioning scheme, and level of atomic orbital (AO) truncation are investigated on a selection of reactions from the literature. The Huzinaga projection approach proves to be more reliable than the level-shift projection when paired with other procedural options. Active subsystem partitioning from the subsystem projected AO decomposition (SPADE) procedure proves slightly better than the combination of Pipek–Mezey localization and Mulliken population screening (PMM). Along with these two options, a new partitioning criteria is proposed based on subsystem von Neumann entropy and the related subsystem orbital occupancy. This new method overlaps with the previous PMM method, but the screening process is computationally simpler. Finally, AO truncation proves to be a robust option for the tested systems when paired with the Huzinaga projection, with satisfactory results being acquired at even the most severe truncation level.

DOE Contract Number(s)

AC05-76RL01830; 17-SC-20-SC

Language

en

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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