Abstract
Intermolecular interactions play an important role for the understanding of catalysis, biochemistry and pharmacy. Double-hybrid density functionals (DHDFs) combine the proper treatment of short-range interactions of common density functionals with the correct description of long-range interactions of wave-function correlation methods. Up to now, there are only a few benchmark studies available examining the performance of DHDFs in condensed phase. We studied the performance of a small but diverse selection of DHDFs implemented within Gaussian and plane waves formalism on cohesive energies of four representative dispersion interaction dominated crystal structures. We found that the PWRB95 and B97X-2 functionals provide an excellent description of long-ranged interactions in solids. In addition, we identified numerical issues due to the extreme grid dependence of the underlying density functional for PWRB95. The basis set superposition error (BSSE) and convergence with respect to the super cell size are discussed for two different large basis sets.
Highlights
Electronic structure calculations for realistic condensed-phase systems are generally more involved than those for molecules
We found the convergence of total energies of meta-hybrid density functionals (HDFs) PW6B95 and PWRB95 requires very tight energy cutoffs for the auxiliary plane waves (PW) basis of at least 4000 Ry
Due to the dependence on the grid parameters, the functionals PW6B95 and PWRB95 are more difficult to use than others: care must be taken to check whether the results are converged with respect to the grid parameters, in CP2K, the density cutoff
Summary
Electronic structure calculations for realistic condensed-phase systems are generally more involved than those for molecules. The former include more atoms and are performed under periodic boundary conditions (PBC), implying interactions between periodic images. Condensed-phase electronic structure modelling often relies on simple approximations. Tight-binding approaches—semiempirical methods, density functional based tight-binding (DFTB)—used to be the work horse in the field. With increased computational power Kohn-Sham density functional theory (KS DFT) [1] became a standard approach.
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