Abstract
A nonempirical quantum mechanical method for the efficient and accurate quantification and analysis of intermolecular interactions is presented and tested on existing benchmark sets. The leading idea here is to focus on the intermolecular part of the correlation energy that contains the all-important London dispersion (LD) interaction. To keep the cost of the method low, essentially at the level of a Hartree-Fock (HF) calculation, the intramolecular part of the correlation energy is neglected. We also neglect the nondispersive parts of the intermolecular correlation energy. This scheme that we denote as Hartree-Fock plus London dispersion (HFLD) can be readily realized on the basis of the recently reported multilevel implementation of the domain-based local pair natural orbital coupled-cluster (DLPNO-CC) theory in conjunction with the well-established local energy decomposition (LED) analysis. The accuracy and efficiency of the HFLD method are evaluated on rare gas dimers, on the S66 and L7 benchmark sets of noncovalent interactions, and on an additional set (LP14) consisting of bulky Lewis pairs held together by intermolecular interactions of various strengths, with interaction energies ranging from -8 to -107 kcal/mol. It is first shown that the LD energy calculated with this approach is essentially identical to that obtained from the full DLPNO-CCSD(T)/LED calculation, with a mean absolute error of 0.2 kcal/mol on the S66 benchmark set. Moreover, in terms of the overall interaction energies, the HFLD method shows an efficiency that is comparable to that of the HF method, while retaining an accuracy between that of the DLPNO-CCSD and DLPNO-CCSD(T) schemes. Since the underlying DLPNO-CCSD method is linear scaling with respect to the system size, the HFLD approach also does not lead to new bottlenecks for large systems. As an illustrative example of its efficiency, the HFLD scheme was applied to the interaction between the substrate and the residues in the active site of the cyclohexanone monooxygenase enzyme. The excellent cost/performance ratio indicates that the HFLD method opens new avenues for the accurate calculation and analysis of noncovalent interaction energies in large molecular systems.
Highlights
Noncovalent interactions (NCIs) play an essential role in chemistry and biology
By exploiting the local nature of electron correlation, linear scaling local variants of the CCSD(T) method can be developed.[34−36] In particular, the domain-based local pair natural orbital CCSD(T) method, i.e., DLPNO-CCSD(T),[36−45] typically retains the accuracy and reliability of its canonical counterpart while allowing at the same time for the calculation of single-point energies for systems with thousands of basis functions.[45−48] Recently, we developed a new Energy decomposition analysis (EDA) approach called local energy decomposition (LED),[49,50] which decomposes the DLPNO
The performance of the Hartree−Fock plus London dispersion (HFLD) method for the calculation of London dispersion (LD) energies and interaction energies is tested on the noble gas dimers as well as on S66, LP14, and L7/5
Summary
Noncovalent interactions (NCIs) play an essential role in chemistry and biology. For instance, they are responsible for the stereoselectivity of asymmetric reactions, the formation of prereactive intermediates, and the folding of proteins.[1]Many quantum mechanical methods can be used to accurately quantify intermolecular NCI energies using either perturbative or supermolecular approaches. Noncovalent interactions (NCIs) play an essential role in chemistry and biology. They are responsible for the stereoselectivity of asymmetric reactions, the formation of prereactive intermediates, and the folding of proteins.[1]. Many quantum mechanical methods can be used to accurately quantify intermolecular NCI energies using either perturbative or supermolecular approaches. The Hamiltonian of a molecular adduct is expressed as that of its constituting noninteracting fragments plus a series of perturbing potentials representing the intermolecular interaction. The most successful approach in this context is symmetry adapted perturbation theory (SAPT).[2]. SAPT as well as its density functional theory (DFT)-SAPT3−6 and extended SAPT (XSAPT)[7−9] variants quantify NCIs accurately and provide a useful breakdown of the exchange-repulsion, electrostatic, induction, and London dispersion (LD) contributions to the intermolecular interaction
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