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Issue 22, 2011
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Quantum mechanics/molecular mechanics methods can be more accurate than full quantum mechanics in systems involving dispersion correlations

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Abstract

The performance of ONIOM(DFT:MM) methods on the structural description of molecules where intramolecular non-covalent interactions play a critical role is examined systematically and compared with that of full DFT methods, both with and without explicit dispersion corrections. The more detailed study is carried out on dithienobicyclo-[4.4.1]-undeca-3,8-diene-11-one ethylene glycol ketal molecule (CSD entry:RESVAN). Accurate description of the non-covalent interactions between two thiophene rings, measured by the optimal S–S distance (X-ray structure 4.29 Å and estimated experimental gas-phase value 4.19 Å), is accomplished by ONIOM(B3LYP:OPLS_2001) [r(S–S) ≈ 4.20 Å] and ONIOM(B3LYP:MMFFs) [r(S–S) ≈ 4.30 Å] calculations, providing results of similar quality to those of dispersion energy corrected density functionals such as B97D [r(S–S) = 4.25 Å], B3LYP-D [r(S–S) = 4.25 Å], and TPSS-D [r(S–S) = 4.22 Å], and much more accurate than those of more conventional density functionals such as B3LYP [r(S–S) = 4.65 Å]. The trends were confirmed by calculations on three other molecules with ONIOM(B3LYP:UFF) and full DFT methods.

Graphical abstract: Quantum mechanics/molecular mechanics methods can be more accurate than full quantum mechanics in systems involving dispersion correlations

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Publication details

The article was received on 23 Dec 2010, accepted on 11 Mar 2011 and first published on 21 Apr 2011


Article type: Paper
DOI: 10.1039/C0CP02957B
Citation: Phys. Chem. Chem. Phys., 2011,13, 10520-10526
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    Quantum mechanics/molecular mechanics methods can be more accurate than full quantum mechanics in systems involving dispersion correlations

    W. M. C. Sameera and F. Maseras, Phys. Chem. Chem. Phys., 2011, 13, 10520
    DOI: 10.1039/C0CP02957B

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