Accurate dipole polarizabilities for water clusters n=2–12 at the coupled-cluster level of theory and benchmarking of various density functionals

Abstract

The static dipole polarizabilities of water clusters (2<or=N<or=12) are determined at the coupled-cluster level of theory (CCSD). For the dipole polarizability of the water monomer it was determined that the role of the basis set is more important than that of electron correlation and that the basis set augmentation converges with two sets of diffuse functions. The CCSD results are used to benchmark a variety of density functionals while the performance of several families of basis sets (Dunning, Pople, and Sadlej) in producing accurate values for the polarizabilities was also examined. The Sadlej family of basis sets was found to produce accurate results when compared to the ones obtained with the much larger Dunning basis sets. It was furthermore determined that the PBE0 density functional with the aug-cc-pVDZ basis set produces overall remarkably accurate polarizabilities at a moderate computational cost.

Distributed Atomic Polarizabilities of Amino Acids and their Hydrogen-Bonded Aggregates

“…As concluded by Hammond et al 8 for water clusters at various coupled-cluster levels of theory, triple or higher excitations are less significant as the number of molecules increases. Noteworthy, the calculation of amino acid aggregates is currently very challenging at the CCSDT level of theory even with the smaller aug-cc-pVDZ basis set.…”

“…The performance of DFT have been rigorously investigated for the polarizabilities of large water clusters. 8 It was found that the accuracy of post-Hartree-Fock levels of theory was not sufficiently higher than that of DFT to justify the increased computational costs. In this work, we aim at extend this analysis to amino acid aggregates, through a careful estimation of the cost/benefits and the marginal utility of extending the level of theory.…”

The Role of Hydrogen Bond in Designing Molecular Optical Materials

“…Most of the calculations in this work were performed using the modest-size cc-pVDZ basis-set. Even though augmentation with diffuse functions is highly desirable to accurately estimate electric moments and polarizabilities of molecules in an infinitely diluted gas, these functions are less relevant for estimating properties in aggregates or crystals, due to the existence of a "basis-set superposition" effect that takes place among basis-sets of vicinal groups or molecules in aggregation, see for example [14]. Otero et al [15] criticized the use of Equation (1) partitioned into their atomic contributions, without guaranteeing that the corresponding atomic basins are kept constant in the process.…”

Hydrogen Bonds and van der Waals Forces in Ice at Ambient and High Pressures

“…Incorporation of a fraction of Hartree-Fock exchange in to the GGAs is an established approach for alleviating this problem. In particular, a popular PBE-based hybrid functional, PBE0 [27], widens the HOMO-LUMO gap of the isolated water molecule by ∼40% and provides more accurate polarizabilities and interaction energies within a variety of water clusters [28][29][30]. When applied to ice, the lattice energies obtained with PBE0 (Table I) are indeed improved over PBE, however, the energy difference between ice Ih and ice VIII is still about four times larger than the experimental value.…”