Dissociation in Binary Acid/base Clusters: An Examination of Inconsistencies Introduced into the Many-Body Expansion by Naïve Fragmentation Schemes

Abstract

Certain processes, such as proton transfer or dissociation, can introduce inconsistencies into computational techniques based on the many-body expansion if the identities of the fragments that define the expansion change. This report uses simple binary acid/base clusters to illustrate this potential problem and to quantify the effects of these inconsistencies on the total and relative electronic energies of the clusters. The 2-body:Many-body CCSD(T):MP2 approach developed in our lab typically deviates from CCSD(T) reference values by only a few hundredths of a kcal mol−1 for clusters in which monomer-based fragment definitions are entirely consistent. These deviations generally grow to at least several tenths of a kcal mol−1 for clusters where inconsistencies are introduced by such simple fragment definitions. In fact, the magnitude of the discrepancies can actually exceed 1 kcal mol−1 (or 25%) for the relative electronic energies.

Department(s)

Chemistry

Comments

National Science Foundation, Grant 1338056

Keywords and Phrases

Acid dissociation; Hydrogen bonding; Many-body expansion; Noncovalent clusters; Proton transfer

International Standard Serial Number (ISSN)

1875-5232; 1574-1400

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

01 Jan 2017

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