Integrated quantum mechanical approaches for extended π systems: Multicentered QM/QM studies of the cyanogen and diacetylene trimers

Hopkins, Brian W.; Tschumper, Gregory S.

doi:10.1016/j.cplett.2005.03.115

Cited by 39 publications

(39 citation statements)

References 24 publications

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“…115 By using high-level CCSD(T) studies of diacetylene and cyanide coupled with MP2 calculations performed on homo-and heterodimers of benzene and triazine, they conclude that mixed dimer systems with pi (though not aromatic) density do show unique electrostatic effects that make them more energetically favourable than indicated by previous studies of usually heterocycle-free homodimer calculations. 116,117 The Sherrill group has also relied on detailed SAPT calculations on pairs of benzene and pyridine and concluded that while dispersion is the largest stabilizing factor in parallel-offset stacks (in their work, preferred over T-shaped pairs), exchange-repulsion often cancels much of this factor, making the contribution of electrostatics relevant once more. 37 They also observe that the introduction of heteroatoms into an aromatic system shrinks its volume and makes it less polarizable; heteroatoms also make the orientation of the monomers more energetically important, as they introduce asymmetry and therefore increase the number of possible pairwise conformations to investigate.…”

Section: Theoretical Investigations Beyond Benzene and Toluenementioning

confidence: 99%

Rethinking the term “pi-stacking”

2012

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Section: Theoretical Investigations Beyond Benzene and Toluenementioning

confidence: 99%

Rethinking the term “pi-stacking”

2012

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“…To recover higher-order n -body interaction energies ( n ≥ 4), which are dominated by classical induction, we adopt an ONIOM-type formalism that involves some type of calculation on the entire supersystem. The idea to combine ONIOM with a fragment-based method was originally introduced by Tschumper and co-workers, − and later by Raghavachari and co-workers. − The two-layer “molecules-in-molecules” (MIM2) approach, , equivalent to Tschumper’s “ n -body:many-body” technique, can be expressed in ONIOM-style notation as Here, “high” and “low” indicate different levels of theory, with a lower-level calculation performed on the entire supersystem [ E low (super)]. The relationship between eq and the original ONIOM method can be understood schematically using Figure .…”

Section: Theorymentioning

confidence: 99%

Energy-Screened Many-Body Expansion: A Practical Yet Accurate Fragmentation Method for Quantum Chemistry

Liu

Herbert

2019

J. Chem. Theory Comput.

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We introduce an implementation of the truncated many-body expansion, MBE(n), in which the n-body corrections are screened using the effective fragment potential force field, and only those that exceed a specified energy threshold are computed at a quantum-mechanical level of theory. This energy-screened MBE(n) approach is tested at the n = 3 level for a sequence of water clusters, (H 2 O) N=6−34 . A threshold of 0.25 kJ/mol eliminates more than 80% of the subsystem electronic structure calculations and is even more efficacious in that respect than is distance-based screening. Even so, the energyscreened MBE(3) method is faithful to a full-system quantum chemistry calculation to within 1−2 kJ/mol/monomer, even in good quality basis sets such as aug-cc-pVTZ. These errors can be reduced by means of a two-layer approach that involves a Hartree−Fock calculation for the entire cluster. Such a correction proves to be necessary in order to obtain accurate relative energies for conformational isomers of (H 2 O) 20 , but the cost of a full-system Hartree−Fock calculation remains smaller than the cost of three-body subsystem calculations at correlated levels of theory. At the level of second-order Møller− Plesset perturbation theory (MP2), a screened MBE(3) calculation plus a full-system Hartree−Fock calculation is less expensive than a full-system MP2 calculation starting at N = 12 water molecules. This is true even if all MBE(3) subsystem calculations are performed on a single 40-core compute node, i.e., without significant parallelization. Energy-screened MBE(n) thus provides a fragment-based method that is accurate, stable in large basis sets, and low in cost, even when the latter is measured in aggregate computer time.

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“…We then investigate the spatial extent of these interactions as well as the far-field component (i.e., the fraction which is not recovered by the energies of the neighboring dimers) of the various components (Sections 4.3 and 4.4) following the analysis in Refs. 27 and 105.…”

Section: Asymptotic Behavior Of Non-covalent Interactions In Nucleomentioning

confidence: 99%

“…27, 105. Such analysis allows one to quantify non-additive component of the far-field part of the interaction energy.…”

Section: Asymptotic Behavior Of Non-covalent Interactions In Nucleomentioning

confidence: 99%

Noncovalent Interactions in Extended Systems Described by the Effective Fragment Potential Method: Theory and Application to Nucleobase Oligomers

et al. 2010

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The implementation of the effective fragment potential (EFP) method within the Q-CHEM electronic structure package is presented. The EFP method is used to study noncovalent π−π and hydrogen-bonding interactions in DNA strands. Since EFP is a computationally inexpensive alternative to high-level ab initio calculations, it is possible to go beyond the dimers of nucleic acid bases and to investigate the asymptotic behavior of different components of the total interaction energy. The calculations demonstrated that the dispersion energy is a leading component in π-stacked oligomers of all sizes. Exchange-repulsion energy also plays an important role. The contribution of polarization is small in these systems, whereas the magnitude of electrostatics varies. Pairwise fragment interactions (i.e., the sum of dimer binding energies) were found to be a good approximation for the oligomer energy. Disciplines Chemistry CommentsReprinted (adapted) with permission from Journal of Physical Chemistry A 114 (2010) August 10, 2010; ReVised Manuscript ReceiVed: September 30, 2010 The implementation of the effective fragment potential (EFP) method within the Q-CHEM electronic structure package is presented. The EFP method is used to study noncovalent π-π and hydrogen-bonding interactions in DNA strands. Since EFP is a computationally inexpensive alternative to high-level ab initio calculations, it is possible to go beyond the dimers of nucleic acid bases and to investigate the asymptotic behavior of different components of the total interaction energy. The calculations demonstrated that the dispersion energy is a leading component in π-stacked oligomers of all sizes. Exchange-repulsion energy also plays an important role. The contribution of polarization is small in these systems, whereas the magnitude of electrostatics varies. Pairwise fragment interactions (i.e., the sum of dimer binding energies) were found to be a good approximation for the oligomer energy.

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Integrated quantum mechanical approaches for extended π systems: Multicentered QM/QM studies of the cyanogen and diacetylene trimers

Cited by 39 publications

References 24 publications

Rethinking the term “pi-stacking”

Rethinking the term “pi-stacking”

Energy-Screened Many-Body Expansion: A Practical Yet Accurate Fragmentation Method for Quantum Chemistry

Noncovalent Interactions in Extended Systems Described by the Effective Fragment Potential Method: Theory and Application to Nucleobase Oligomers

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