Jump to main content
Jump to site search


Assessment of DFT for endohedral complexes' dipole moment: PNO-LCCSD-F12 as a reference method

Abstract

We present a systematic evaluation of the performance of a wide range of exchange-correlation functionals and related dispersion correction schemes for the computation of dipole moments of endohedral complexes, formed through the encapsulation of an AB molecule (AB = LiF, HCl) inside carbon nanotubes (CNTs) of different diameter. The consistency and accuracy of i) generalized gradient approximation, ii) meta GGA, iii) global hybrid, and iv) range-separated hybrid density functionals are assessed. In total, 37 density functionals are tested. The results obtained using highly accurate pair natural orbitals based explicitly correlated local coupled cluster singles doubles (PNO-LCCSD-F12) method of Werner and co-workers Schwilk et al. J. Chem. Theory Comput. 2017, 13, 3650; Ma et al. J. Chem. Theory Comput. 2017, 13, 4871 with the aug-cc-pVTZ basis set serve as reference. The static electric dipole moment is computed via the finite field response or, when possible, as the expectation value of the dipole operator. Among others, it is shown that functionals belonging to the class of range-separated hybrids, provide results closest to the coupled cluster reference data. In particular, the ωB97X as well as the M11 functionals may be considered as a promising choice for computing electric properties of noncovalent endohedral complexes. On the other hand, the worst performance was found for the functionals which do not include the Hartree-Fock exchange. The analysis of both the coupled cluster and the DFT results indicate a strong coupling of dispersion and polarization that may also explain why lower level DFT methods, as well as Hartree-Fock and MP2, cannot yield dipole moments beyond a qualitative agreement with the higher order reference data. Interestingly, the much smaller and less systematically constructed basis sets of Pople of moderate size provide results of accuracy at least comparable with the extended Dunning's aug-cc-pVTZ basis set.

Back to tab navigation

Supplementary files

Publication details

The article was received on 20 Sep 2018, accepted on 05 Nov 2018 and first published on 05 Nov 2018


Article type: Paper
DOI: 10.1039/C8CP05928D
Citation: Phys. Chem. Chem. Phys., 2018, Accepted Manuscript
  •   Request permissions

    Assessment of DFT for endohedral complexes' dipole moment: PNO-LCCSD-F12 as a reference method

    J. Kozłowska, M. Schwilk, A. Roztoczyńska and W. Bartkowiak, Phys. Chem. Chem. Phys., 2018, Accepted Manuscript , DOI: 10.1039/C8CP05928D

Search articles by author

Spotlight

Advertisements