Abstract

A 3-body:many-body integrated quantum mechanical (QM) fragmentation method for non-covalent clusters is introduced within the ONIOM formalism. The technique captures all 1-, 2-, and 3-body interactions with a high-level electronic structure method, while a less demanding low-level method is employed to recover 4-body and higher-order interactions. When systematically applied to 40 low-lying (H2O)n isomers ranging in size from n = 3 to 10, the CCSD(T):MP2 3-body:many-body fragmentation scheme deviates from the full CCSD(T) interaction energy by no more than 0.07 kcal mol-1 (or < 0.01 kcal mol-1 per water). The errors for this QM:QM method increase only slightly for various low-lying isomers of (H2O)16 and (H2O)17 (always within 0.13 kcal mol-1 of the recently reported canonical CCSD(T)/aug-cc-pVTZ energies). The 3-body:many-body CCSD(T):MP2 procedure is also very efficient because the CCSD(T) computations only need to be performed on subsets of the cluster containing 1, 2, or 3 monomers, which in the current context means the largest CCSD(T) calculations are for 3 water molecules, regardless of the cluster size. © 2011 American Institute of Physics.

Department(s)

Chemistry

Publication Status

Available Access

Comments

National Science Foundation, Grant CHE-0911541

International Standard Serial Number (ISSN)

0021-9606

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2024 American Institute of Physics, All rights reserved.

Publication Date

28 Jul 2011

PubMed ID

21806106

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Chemistry Commons

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