Rationale for mixing exact exchange with density functional approximations

ConspectusDensity Functional Theory (DFT) emerged in the last two decades as the most reliable tool the description and prediction of properties of molecular systems and extended materials, coupling in an unprecedented way high accuracy and reasonable computational cost. This success rests also on the development of more and more performing Density Functional Approximations (DFAs).Indeed, the Achilles' heel of DFT is represented by the exchange-correlation contribution to the total energy, which, being unknown, must be approximated. Since the beginning of the '90s, global hybrids (GH) functionals, where an explicit dependence of the exchange-correlation energy on model. In such a way, a whole family of non-empirical functionals, spanning on the highest rungs of the Perdew's quality scale, is now available and competitive with other -more empirical-DFAs. This is a previous version of the article published in Accounts of Chemical Research. 2016Research. , 49(8): 1503Research. -1513Research. . doi:10.1021 2 Discussion of selected cases, ranging from thermochemistry and reactions to weak interactions and excitations energies, not only show the large range of applicability of non-empirical DFAs, but also underline how increasing the number of theoretical constrains parallel with an improvement of the DFA's numerical performances. This fact further consolidates the strong theoretical framework of non-empirical DFAs.Finally, even if non-empirical DH approaches are still computationally expensive, relying on the fact that they can benefit of all technical enhancements developed for speeding-up post-HartreeFock methods, there is a substantial hope for their near future routine application to the description and prediction of complex chemical systems and reactions.

show abstract

“…Starting from this expression the global-hybrid functional PBE0 can be obtained setting n=4 on the basis of perturbation theory: 2,3,35,36 ( )…”

Section: Theorymentioning

confidence: 99%

Nonempirical Double-Hybrid Functionals: An Effective Tool for Chemists

et al. 2016

View full text Add to dashboard Cite

show abstract

“…It has been then argued [4,5], using results from perturbation theory, than n = 4 is the optimal value for a realistic description of the chemical systems.…”

Section: Theoretical Framework 21 Generalities: Acm and Associated Fmentioning

confidence: 99%

“…That brilliant idea, to replace the exact exchange term by an approximate expression easier to calculate [1], reducing thus the computational scaling by an order of magnitude, is still feeding the field. Admittedly, the blooming of Density Functional Theory (DFT) along last decades has enormously benefited from the above audacity; a major breakthrough was the combination of exact-like and approximate exchange in a hybrid fashion together with the introduction of correlation effects through the corresponding approximate functional form [2][3][4][5][6][7]. But, who will want to go a step further by augmenting an order of magnitude the cost with respect to these hybrid exchange-correlation functionals ?…”

Section: Introductionmentioning

confidence: 99%

Double-hybrid density functionals: merging wavefunction and density approaches to get the best of both worlds

Sancho‐García

Adamo

2013

Phys. Chem. Chem. Phys.

109

108

View full text Add to dashboard Cite

We review in this Perspective why and how double-hybrid density functionals have become new leading actors in the field of computational chemistry, thanks to the combination of an unprecedented accuracy together with large robustness and reliability. Similarly to their predecessors, the widely employed hybrid density functionals, they are rooted on the Adiabatic Connection Method from which they emerge in a natural way. We present recent achievements concerning applications to chemical systems of the most interest, and current extensions to deal with challenging issues such as non-covalent interactions and excitation energies. These promising methods, despite a slightly higher computational cost than other typical density-based models, are called to play a key role in the near future and can thus pave the way towards new discoveries or advances.2

show abstract

“…Gas phase optimizations of all isomers of different [TeXnY6-n] 2-(X = Cl, Y = Br) anions were carried out using the PBE0 density functional [38][39][40][41] and correlation consistent basis sets of triple--valence quality (aug-cc-pVTZ for Cl and Br, and aug-cc-pVTZ-PP for Te) [42][43][44]. The program package [45].…”

Section: Computational Detailsmentioning

confidence: 99%

Identification of mixed bromidochloridotellurate anions in disordered crystal structures of (bdmim)2[TeX2Y4] (X, Y=Br, Cl; bdmim=1-butyl-2,3-dimethylimidazolium) by combined application of Raman spectroscopy and solid-state DFT calculations

Närhi

Kutuniva

Lajunen

et al. 2014

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

View full text Add to dashboard Cite

Laitinen, R. (2014). Identification of mixed bromidochloridotellurate anions in disordered crystal structures of (bdmim)2[TeX2Y4] (X, Y = Br, Cl; bdmim = 1-butyl-2,3 -dimethylimidazolium) by combined application of Raman spectroscopy and solidstate DFT calculations. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 117, 728-738. doi:10.1016/j.saa.2013 1.Introduction.X-ray crystallography provides the most definite means to elucidate structures of different types of materials at the molecular level. However, successful routine structure determinations require crystalline material, which contains well-defined single crystals with ordered, periodically repeating structures. In many cases this is not a case. For instance, disorder and twinning are common occurrences, and the number of modular structures is continually growing. Various techniques have been developed to deal with some of these problems, as exemplified in refs. 1-5, though some types of disorder cannot be resolved by X-ray crystallography alone.Spectroscopic methods have often been evoked to resolve the crystallographic disorder. For instance, crystalline eight-membered SenS8-n ring molecules [6] or [TiCp2SenS5-n] complexes [7] are solid solutions of 30 and 20 molecular species, respectively, taking the presence of isomers into account. Consequently, each chalcogen-atom sites in both compounds are partially occupied by sulfur and selenium atoms. In both cases, individual molecules have been identified by dissolving the crystalline samples, and recording and assigning their 77 Se NMR spectra [6,7].Vibrational spectroscopy is useful in the identification of individual species in disordered crystal

show abstract

Rationale for mixing exact exchange with density functional approximations

Cited by 5,589 publications

References 42 publications

Nonempirical Double-Hybrid Functionals: An Effective Tool for Chemists

Nonempirical Double-Hybrid Functionals: An Effective Tool for Chemists

Double-hybrid density functionals: merging wavefunction and density approaches to get the best of both worlds

Identification of mixed bromidochloridotellurate anions in disordered crystal structures of (bdmim)2[TeX2Y4] (X, Y=Br, Cl; bdmim=1-butyl-2,3-dimethylimidazolium) by combined application of Raman spectroscopy and solid-state DFT calculations

Contact Info

Product

Resources

About