Accurate and Efficient Quantum Chemistry Calculations for Noncovalent Interactions in Many-Body Systems: The XSAPT Family of Methods

Abstract

We present an overview of "XSAPT", a family of quantum chemistry methods for noncovalent interactions. These methods combine an efficient, iterative, monomer-based approach to computing many-body polarization interactions with a two-body version of symmetry-adapted perturbation theory (SAPT). The result is an efficient method for computing accurate intermolecular interaction energies in large noncovalent assemblies such as molecular and ionic clusters, molecular crystals, clathrates, or protein-ligand complexes. As in traditional SAPT, the XSAPT energy is decomposable into physically meaningful components. Dispersion interactions are problematic in traditional low-order SAPT, and two new approaches are introduced here in an attempt to improve this situation: (1) third-generation empirical atom-atom dispersion potentials, and (2) an empirically scaled version of second-order SAPT dispersion. Comparison to high-level ab initio benchmarks for dimers, water clusters, halide-water clusters, a methane clathrate hydrate, and a DNA intercalation complex illustrate both the accuracy of XSAPT-based methods as well as their limitations. The computational cost of XSAPT scales as O(N(3))-O(N(5)) with respect to monomer size, N, depending upon the particular version that is employed, but the accuracy is typically superior to alternative ab initio methods with similar scaling. Moreover, the monomer-based nature of XSAPT calculations makes them trivially parallelizable, such that wall times scale linearly with respect to the number of monomer units. XSAPT-based methods thus open the door to both qualitative and quantitative studies of noncovalent interactions in clusters, biomolecules, and condensed-phase systems.

Thirty years of density functional theory in computational chemistry: an overview and extensive assessment of 200 density functionals

“…The H2O6Bind8 data-set [143] belongs to the NCEC datatype and contains the binding energies of eight isomers of the water hexamer.…”

Fast, accurate evaluation of exact exchange: The occ-RI-K algorithm

“…While PARI-K yields impressive accuracy in its own right, the accuracy of occ-RI-K is clearly superior. The errors per electron in the absolute energies of all molecules in the test set are quite 73,74 0.00 0.00 Butanediol65 75 0.00 0.00 BzDC215 76 0.00 0.00 CT20 77 0.00 0.00 DIE60 78 0.00 0.00 DS14 79 0.00 0.01 EA13 80 0.01 0.01 EIE22 81 0.00 0.00 FmH2O10 82,83 0.01 0.16 ACONF 84,85 0.00 0.01 BHPERI 85,86 0.00 0.00 CYCONF 85,87 0.00 0.00 G21EA 85,88 0.00 0.00 G21IP 85,88 0.00 0.00 NBPRC 85 0.00 0.02 WATER27 85,89 0.00 0.03 NHTBH38 85,90 0.01 0.02 HTBH38 85,91 0.00 0.01 BH76RC 85 0.00 0.00 DBH24 86 0.00 0.01 H2O6Bind8 83,92 0.00 0.05 HB15 93 0.00 0.01 HSG 94,95 0.00 0.00 HW30 96 0.00 0.01 HW6Cl 82,83 0.00 0.04 HW6F 82,83 0.00 0.04 IP13 80 0.00 0.00 NBC10 95 0.01 0.01 NC15 97 0.00 0.00 Pentane14 98 0.00 0.01 RG10 99 0.00 0.00 S22 …”

The electronic mechanism ruling the dihydrogen bonds and halogen bonds in weakly bound systems of H3SiH···HOX and H3SiH···XOH (X = F, Cl, and Br)

“…In line with this, a growing number of experimental and theoretical evidences confirm that hydrogen bonds and halogen bonds [11][12][13][14][15] play a crucial role in research of specific areas as well as interdisciplinary ones, of which we can cite the biochemistry and, in particular, the medicinal chemistry [16][17][18]. On a purely theoretical viewpoint, by means of energy decomposition scheme [19][20][21], scientists have an insight into the nature of hydrogen bonds and halogen bonds and think that the electrostatic interaction, polarization, charge transfer, and dispersion are all responsible for the stability of intermolecular complexes formed in light of these interactions [22]. Nevertheless, some research groups have appreciated a deeper recognition that halogen bonding involves the interaction of positive σ-holes (positive regions of electrostatic potential on the extensions of the covalent bond to the halogen) on the halogen with negative sites on other molecules [23,24].…”

“…Furthermore, the intermolecular strength of the halogen bond complexes is deeply weak just like is observed in dispersive intermolecular complexes [77] or even stacking structures [78], and in some cases here, particularly the IV complex, whose interaction seems to be repulsive. In this assertion, we would like to emphasize that energy decomposition analysis was not made, although we are willing to include this topic in our discussion not at this current time, but actually in future works [19][20][21]. Table 4 enumerates the values of the NBO atomic charges (q) as well as the variations (Δq) on the linkage elements, namely as qH (Si) and qH (HOX) , as well as those electronegative ones symbolized by qO and qX.…”