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Title: ONIOM Study of Chemical Reactions in Microsolvation Clusters: (H2O)(n)CH3Cl+OH-(H2O)(m) (n+m = 1 and 2)

Abstract

The reliability of the two-layered ONIOM (our own N-layered molecular orbital + molecular mechanics) method was examined for the investigation of the SN2 reaction pathway (reactants, reactant complexes, transition states, product complexes, and products) between CH3Cl and an OH- ion in microsolvation clusters with one or two water molecules. Only the solute part, CH3Cl and OH-, was treated at a high level of molecular orbital (MO) theory, and all solvent water molecules were treated at a low MO level. The ONIOM calculation at the MP2 (Moller-Plesset second order perturbation)/aug-cc-pVDZ (augmented correlation-consistent polarized valence double-zeta basis set) level of theory as the high level coupled with the B3LYP (Becke 3 parameter-Lee-Yag-Parr)/6-31+G(d) as the low level was found to reasonably reproduce the "target"geometries at the MP2/aug-cc-pVDZ level of theory. The energetics can be further improved to an average absolute error of <1.0 kcal/mol per solvent water molecule relative to the target CCSD(T) (coupled cluster singles and doubles with triples by perturbation)/aug-cc-pVDZ level by using the ONIOM method in which the high level was CCSD(T)/aug-cc-pVDZ level with the low level of MP2/aug-cc-pVDZ. The present results indicate that the ONIOM method would be a powerful tool for obtaining reliable geometries and energetics for chemicalmore » reactions in larger microsolvated clusters with a fraction of cost of the full high level calculation, when an appropriate combination of high and low level methods is used. The importance of a careful test is emphasized.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
15004172
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A, 105(30):7185-7197
Additional Journal Information:
Journal Volume: 105; Journal Issue: 30; Journal ID: ISSN 1089-5639
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMICAL REACTIONS; RELIABILITY; SOLUTES; SOLVENTS; TARGETS; VALENCE; WATER; Environmental Molecular Sciences Laboratory

Citation Formats

Re, Suyong, and Morokuma, Keiji. ONIOM Study of Chemical Reactions in Microsolvation Clusters: (H2O)(n)CH3Cl+OH-(H2O)(m) (n+m = 1 and 2). United States: N. p., 2001. Web. doi:10.1021/jp004623a.
Re, Suyong, & Morokuma, Keiji. ONIOM Study of Chemical Reactions in Microsolvation Clusters: (H2O)(n)CH3Cl+OH-(H2O)(m) (n+m = 1 and 2). United States. https://doi.org/10.1021/jp004623a
Re, Suyong, and Morokuma, Keiji. 2001. "ONIOM Study of Chemical Reactions in Microsolvation Clusters: (H2O)(n)CH3Cl+OH-(H2O)(m) (n+m = 1 and 2)". United States. https://doi.org/10.1021/jp004623a.
@article{osti_15004172,
title = {ONIOM Study of Chemical Reactions in Microsolvation Clusters: (H2O)(n)CH3Cl+OH-(H2O)(m) (n+m = 1 and 2)},
author = {Re, Suyong and Morokuma, Keiji},
abstractNote = {The reliability of the two-layered ONIOM (our own N-layered molecular orbital + molecular mechanics) method was examined for the investigation of the SN2 reaction pathway (reactants, reactant complexes, transition states, product complexes, and products) between CH3Cl and an OH- ion in microsolvation clusters with one or two water molecules. Only the solute part, CH3Cl and OH-, was treated at a high level of molecular orbital (MO) theory, and all solvent water molecules were treated at a low MO level. The ONIOM calculation at the MP2 (Moller-Plesset second order perturbation)/aug-cc-pVDZ (augmented correlation-consistent polarized valence double-zeta basis set) level of theory as the high level coupled with the B3LYP (Becke 3 parameter-Lee-Yag-Parr)/6-31+G(d) as the low level was found to reasonably reproduce the "target"geometries at the MP2/aug-cc-pVDZ level of theory. The energetics can be further improved to an average absolute error of <1.0 kcal/mol per solvent water molecule relative to the target CCSD(T) (coupled cluster singles and doubles with triples by perturbation)/aug-cc-pVDZ level by using the ONIOM method in which the high level was CCSD(T)/aug-cc-pVDZ level with the low level of MP2/aug-cc-pVDZ. The present results indicate that the ONIOM method would be a powerful tool for obtaining reliable geometries and energetics for chemical reactions in larger microsolvated clusters with a fraction of cost of the full high level calculation, when an appropriate combination of high and low level methods is used. The importance of a careful test is emphasized.},
doi = {10.1021/jp004623a},
url = {https://www.osti.gov/biblio/15004172}, journal = {Journal of Physical Chemistry A, 105(30):7185-7197},
issn = {1089-5639},
number = 30,
volume = 105,
place = {United States},
year = {Sat Jul 07 00:00:00 EDT 2001},
month = {Sat Jul 07 00:00:00 EDT 2001}
}