Performance of DFT methods in the calculation of isotropic and dipolar contributions to 14N hyperfine coupling constants of nitroxide radicals

Oleg I Gromov; Sergei V Kuzin; Elena N Golubeva

doi:10.1007/s00894-019-3966-y

Performance of DFT methods in the calculation of isotropic and dipolar contributions to ¹⁴N hyperfine coupling constants of nitroxide radicals

J Mol Model. 2019 Mar 11;25(4):93. doi: 10.1007/s00894-019-3966-y.

Authors

Oleg I Gromov¹, Sergei V Kuzin², Elena N Golubeva²

Affiliations

¹ Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991. aalchm@gmail.com.
² Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991.

PMID: 30859325
DOI: 10.1007/s00894-019-3966-y

Abstract

In the present study, we tested the widely used density functionals BP86, PBE, OLYP, TPSS, M06-L, B3LYP, PBE0, mPW1PW, B97, BHandHLYP, TPSS0, M06, M06-2X, CAM-B3LYP, ωB97x, and B2PLYP with the cc-pCVQZ basis set in calculations on a set of 23 nitroxide radicals with well-resolved ¹⁴N anisotropic hyperfine coupling (HFC) constants. The results were compared with those obtained using the B3LYP/N07D and PBE/N07D methods. The convergence of the HFC values to the complete basis set limit is briefly discussed. The best results were obtained using the M06/COSMO method, with a mean absolute deviation (MAD) of 0.4 G for the dipole-dipole contribution and MAD = 0.6 G for the contact coupling contribution (as compared to 1.1 G and 1.0 G, respectively, for the B3LYP/N07D/COSMO method and 1.7 G and 0.5 G, respectively, for the B3LYP/N07D method). The majority of the functionals yielded satisfactory results for the dipole-dipole contribution, but only the M06 functional yielded similar errors for both the dipole-dipole and isotropic contributions. The RIJCOSX and RI approximations introduced errors equal to or smaller than 0.01 G.

Keywords: Benchmark; DFT; EPR spectroscopy; Hyperfine coupling; Nitroxide radical.

Abstract

Grants and funding