Perspectives on Basis Sets Beautiful: Seasonal Plantings of Diffuse Basis Functions

Abstract

We present a perspective on the use of diffuse basis functions for electronic structure calculations by density functional theory and wave function theory. We especially emphasize minimally augmented basis sets and calendar basis sets. We base our conclusions on our previous experience with commonly computed quantities, such as bond energies, barrier heights, electron affinities, noncovalent (van der Waals and hydrogen bond) interaction energies, and ionization potentials, on Stephens et al.'s results for optical rotation and on our own new calculations (presented here) of polarizabilities and of potential energy curves of van der Waals complexes. We emphasize the benefits of partial augmentation of the higher-zeta basis sets in preference to full augmentation at a lower ζ level. Benefits and limitations of the use of fully, partially, and minimally augmented basis sets are reviewed for different electronic structure methods and molecular properties. We have found that minimal augmentation is almost always enough for density functional theory (DFT) when applied to ionization potentials, electron affinities, atomization energies, barrier heights, and hydrogen-bond energies. For electric dipole polarizabilities, we find that augmentation beyond minimal has an average effect of 8% at the polarized triple-ζ level and 5% at the polarized quadruple-ζ level. The effects are larger for potential energy curves of van der Waals complexes. The effects are also larger for wave function theory (WFT). Even for WFT though, full augmentation is not needed for most purposes, and a level of augmentation between minimal and full is optimal for most problems. The calendar basis sets named after the months provide a convergent sequence of partially augmented basis sets that can be used for such calculations. The jun-cc-pV(T+d)Z basis set is very useful for MP2-F12 calculations of barrier heights and hydrogen bond strengths.

Rubrene: The Interplay between Intramolecular and Intermolecular Interactions Determines the Planarization of Its Tetracene Core in the Solid State

“…To assess this point, SAPT0/jun-cc-pVDZ calculations 27,31,36,38 (simplified throughout the remainder of the discussion as SAPT0) were employed. Here, we thus focus solely on phenyl pairs that are extracted from the tetracene backbone with the dangling bonds on the phenyl groups terminated with hydrogen atoms.…”

Arsenic Adsorption onto Minerals: Connecting Experimental Observations with Density Functional Theory Calculations

“…In addition to using an electron correlation method such as MP or DFT, it is necessary to specify a basis set when using molecular orbital (MO) calculations [136,[148][149][150][151]; however, when using planewave calculations [152][153][154][155][156][157][158], basis sets are not used.…”

“…All energy minimization calculations on the cluster models were performed without symmetry or atomic constraints. Energy minimizations, frequency, and kinetics (transition state) calculations were performed using the hybrid density functional B3LYP with the 6-31G(d) basis set [148][149][150][151]. B3LYP accounts for E xc and the 6-31G(d) basis set is a DZ basis set with p-polarization functions on the non-H atoms.…”

“…The polarized continuum places the model in the cavity of a field with a constant permittivity, in this case for water; this field is used as a proxy for the solvent of interest. Single-point energy calculations were performed with the B3LYP functional and the 6-31+G(d,p) basis set [148][149][150][151]; the TZ basis set with augmented functions on the non-H atoms, and d-polarized and p-polarized functions for the non-H atoms and H-atoms, respectively, was used in order to improve the accuracy of the energy that was calculated using B3LYP/6-31(d) during the energy minimizations; this is a standard practice. The ΔG ads was then determined from stoichiometrically balanced reactions.…”

Estudos Teóricos de Misturas Álcool-Água e Seus Efeitos em Propriedades Eletrônicas em um Derivado de Quinolina

“…Sendo que a melhora mais signi cativa no conjunto de base vêm com a adição das funções do tipo d. Também pode-se adicionar funções difusas do tipo s e p ao conjunto de base para átomos pesados, o que pode melhorar a descrição da distribuição eletrônica em ânions e de interações mais fracas, como ligações de hidrogênio [93]. A adição de funções difusas é simbolizada pela inclusão de um + ao acrônimo do conjunto de base, assim com essa adição o conjunto 6-311G** se torna 6-311+G**.…”