An accurate and efficient computational protocol for obtaining the complete basis set limits of the binding energies of water clusters at the MP2 and CCSD(T) levels of theory: Application to (H2O)m, m = 2-6, 8, 11, 16, and 17

Abstract

We report MP2 and Coupled Cluster Singles, Doubles, and perturbative Triples [CCSD(T)] binding energies with basis sets up to pentuple zeta quality for the (H2O)m=2-6,8 water clusters. Our best CCSD(T)/Complete Basis Set (CBS) estimates are -4.99 ± 0.04 kcal/mol (dimer), -15.8 ± 0.1 kcal/mol (trimer), -27.4 ± 0.1 kcal/mol (tetramer), -35.9 ± 0.3 kcal/mol (pentamer), -46.2 ± 0.3 kcal/mol (prism hexamer), -45.9 ± 0.3 kcal/mol (cage hexamer), -45.4 ± 0.3 kcal/mol (book hexamer), -44.3 ± 0.3 kcal/mol (ring hexamer), -73.0 ± 0.5 kcal/mol (D2d octamer), and -72.9 ± 0.5 kcal/mol (S4 octamer). We have found that the percentage of both the uncorrected (De) and basis set superposition error-corrected (De (CP)) binding energies recovered with respect to the CBS limit falls into a narrow range on either sides of the CBS limit for each basis set for all clusters. In addition, this range decreases upon increasing the basis set. Relatively accurate estimates (within <0.5%) of the CBS limits can be obtained when using the "23, 13" (for the AVDZ set) or the "12, 12" (for the AVTZ, AVQZ, and AV5Z sets) mixing ratio between De and De (CP). These mixing rations are determined via a least-mean-squares approach from a dataset that encompasses clusters of various sizes. Based on those findings, we propose an accurate and efficient computational protocol that can be presently used to estimate accurate binding energies of water clusters containing up to 30 molecules (for CCSD(T)) and up to 100 molecules (for MP2).

Performance of polarization-consistent vs. correlation-consistent basis sets for CCSD(T) prediction of water dimer interaction energy

“…However, in some cases in the current studies, we noticed a reverse situation for the limiting value (the CBSextrapolated raw energy was less attractive than the CP corrected). A similar and unrealistic raw (− 4.95 kcal/mol) and CP-corrected energy (− 5.02 kcal/mol) ordering also reported Xantheas [42].…”

Ring‐Stacking Water Clusters: Morphology and Stabilities

“…Their theoretical studies provide new insights into the mechanism of chiral recognition in small water clusters, especially for monocyclic water clusters, at the atomic level. Recently, an accurate and efficient computational protocol, i. e., second order approximation of Møller-Plesset perturbation theory (MP2) and Coupled Cluster Singles and Doubles (Triple) (CCSD(T)) based on perturbative method, for characterization of waters clusters is reviewed by Tschumper et al [21] and Xantheas et al [22] Some of these high-level studies showed the electronic structure of water clusters as large as (H 2 O) 17 . Accurate energetics of hydrogen bonds in water clusters are important not only for the development of interaction potentials for water, but also for assessing the accuracy of other theoretical approaches.…”

“…Recently, an accurate and efficient computational protocol, i. e., second order approximation of Møller–Plesset perturbation theory (MP2) and Coupled Cluster Singles and Doubles (Triple) (CCSD(T)) based on perturbative method, for characterization of waters clusters is reviewed by Tschumper et al . and Xantheas et al . Some of these high‐level studies showed the electronic structure of water clusters as large as (H 2 O) 17 .…”

“…It has also been proposed that the small cyclic water clusters (tetramer, pentamer and hexamer) are the basic building units for larger (n≤20) water clusters, particularly when the size of the clusters n is a multiple of 4, 5 or 6. For example, the lowest‐energy isomers of water clusters (H 2 O) 8,10,15 have been reported to be formed by stacking the tetramers or pentamers . The structures of the water clusters (H 2 O) 12,18,20 also follow the ring‐stacking motif but the lowest‐energy isomers are still a subject of debate due to the existence of various possible energetically competing ring‐stacking isomers .…”

Thermally Induced Hydrogen-Bond Rearrangements in Small Water Clusters and the Persistent Water Tetramer

“…The lowest energy isomers for n = 3 – 5 are cyclic, with monotonically increasing HB strengths. 18 Thus, one might expect the transition temperatures to increase monotonically with n . Figure 5 shows P ( r ) for these three clusters from which the onset of bifurcation, melting, and vaporization can be gleaned as upward deviating tails in comparison to the SND.…”