Accurate calculation of binding energies for molecular clusters – Assessment of different models

Friedrich, Joachim; Fiedler, Benjamin

doi:10.1016/j.chemphys.2016.02.022

Cited by 2 publications

(9 citation statements)

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“…There has been considerable interest in predicting the relative energies of various molecular clusters, both qualitatively and quantitatively. [67][68][69] More often than not, hydrogen bonded molecules in clusters interact in a non-pairwise fashion, 64,65 making the total binding energy not a simple sum of pairwise interaction energies. It has been shown that homodromic hydrogen bonding ring-like networks are associated with the highest cooperativity.…”

Section: Water Pentamer Conformersmentioning

confidence: 99%

Making many-body interactions nearly pairwise additive: The polarized many-body expansion approach

Veccham

Head‐Gordon

2019

The Journal of Chemical Physics

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The Many-Body Expansion (MBE) is a useful tool to simulate condensed phase chemical systems, often avoiding the steep computational cost of usual electronic structure methods. However, it often requires higher than 2-body terms to achieve quantitative accuracy. In this work, we propose the Polarized MBE (PolBE) method where each MBE energy contribution is treated as an embedding problem. In each energy term, a smaller fragment is embedded into a larger, polarized environment and only a small region is treated at the high-level of theory using embedded mean-field theory. The role of polarized environment was found to be crucial in providing quantitative accuracy at the 2-body level. PolBE accurately predicts non-covalent interaction energies for a number of systems, including CO 2 , water, and hydrated ion clusters, with a variety of interaction mechanisms, from weak dispersion to strong electrostatics considered in this work. We further demonstrate that the PolBE interaction energy is predominantly pairwise unlike the usual vacuum MBE which requires higher-order terms to achieve similar accuracy. We numerically show that PolBE often performs better than other widely used embedded MBE methods such as the electrostatically embedded MBE.Owing to the lack of expensive diagonalization of Fock matrices and its embarrassingly parallel nature, PolBE is a promising way to access condensed phase systems with hybrid density functionals that are difficult to treat with currently available methods.

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Section: Water Pentamer Conformersmentioning

confidence: 99%

Making many-body interactions nearly pairwise additive: The polarized many-body expansion approach

Veccham

Head‐Gordon

2019

The Journal of Chemical Physics

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“…In this context, the basis set superposition error (BSSE) is a well-known problem, which results in large errors, especially when using small basis sets without a CP correction. Previously, it has been shown that the combination of the standard incremental scheme with the focal-point approach is also suitable to provide accurate binding energies in a very efficient way . Nevertheless it is always useful to have another ansatz for the estimation of the CBS limit at hand, for example, the use of larger basis sets within the incremental scheme together with corresponding CBS extrapolations.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the domain-specific basis set approach, the common incremental scheme features an exceedingly high efficiency in this case, which is further increased by the application of PNOs in this work. Therefore, we analyzed the accuracy of our PNO-based incremental scheme with respect to our highly accurate reference for a set of 4 cluster structures and took into account both the focal-point approach as well as larger target basis sets and corresponding two-point CBS(XY) extrapolations. , …”

Section: Resultsmentioning

confidence: 99%

“…The method is also assessed for clusters of small molecules. Therefore, we used a test set of 4 clusters ((H 2 ) 20 , (CH 4 ) 10 , (HF) 10 , (H 2 O) 10 ), which have recently been considered . Furthermore, a (H 2 O) 20 dodecahedron structure from a previous work was also applied …”

Section: Computational Detailsmentioning

confidence: 99%

“…However, the BSIE can be reduced at rather small computational cost by either CBS extrapolations, , the application of explicitly correlated methods, − or the estimation with a lower-level method like MP2. − The latter approach is simple and very efficient, as the CCSD(T) calculation has to be performed only with a small basis set, but due to an MP2 increment, the results feature the accuracy of the large basis. Recently, this focal-point method has been successfully used in combination with our incremental scheme …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Combining Accuracy and Efficiency: An Incremental Focal-Point Method Based on Pair Natural Orbitals

Fiedler

Schmitz

Hättig

et al. 2017

J. Chem. Theory Comput.

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In this work, we present a new pair natural orbitals (PNO)-based incremental scheme to calculate CCSD(T) and CCSD(T0) reaction, interaction, and binding energies. We perform an extensive analysis, which shows small incremental errors similar to previous non-PNO calculations. Furthermore, slight PNO errors are obtained by using T = T with appropriate values of 10 to 10 for reactions and 10 for interaction or binding energies. The combination with the efficient MP2 focal-point approach yields chemical accuracy relative to the complete basis-set (CBS) limit. In this method, small basis sets (cc-pVDZ, def2-TZVP) for the CCSD(T) part are sufficient in case of reactions or interactions, while some larger ones (e.g., (aug)-cc-pVTZ) are necessary for molecular clusters. For these larger basis sets, we show the very high efficiency of our scheme. We obtain not only tremendous decreases of the wall times (i.e., factors >10) due to the parallelization of the increment calculations as well as of the total times due to the application of PNOs (i.e., compared to the normal incremental scheme) but also smaller total times with respect to the standard PNO method. That way, our new method features a perfect applicability by combining an excellent accuracy with a very high efficiency as well as the accessibility to larger systems due to the separation of the full computation into several small increments.

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Accurate calculation of binding energies for molecular clusters – Assessment of different models

Cited by 2 publications

References 129 publications

Making many-body interactions nearly pairwise additive: The polarized many-body expansion approach

Making many-body interactions nearly pairwise additive: The polarized many-body expansion approach

Combining Accuracy and Efficiency: An Incremental Focal-Point Method Based on Pair Natural Orbitals

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