Performance of the DLPNO-CCSD and Recent DFT Methods in the Calculation of Isotropic and Dipolar Contributions to 14N Hyperfine Coupling Constants of Nitroxide Radicals

In the present study, the performance of a set of density functionals: BP86, PBE, OLYP, BEEF, PBEpow, TPSS, SCAN, PBEGXPBE, M06L, MN15L, B3LYP, PBE0, mPW1PW, B97, BHandHLYP, mPW1PW, HSE06, B98, TPSS0, PBE1KCIS, SCAN0, M06, M06-2X, MN15, CAM-B3LYP, ωB97x, B2PLYP, and the B3LYP/N07D and PBE/N07D schemes in the calculation of the 14N anisotropic hyperfine coupling (HFC) constants of a set of 23 nitroxide radicals is evaluated. The results are compared with those obtained with the DLPNO-CCSD method and experimental HFC values. Harmonic contribution to the 14N HFC vibrational correction was calculated at the revPBE0/def2-TZVPP level and included in the evaluation. With the vibrational correction, the DLPNO-CCSD method yielded HFC values in good agreement with the experiment (MAD = 0.3 G for the dipole-dipole contribution and MAD = 0.8 G for the contact coupling contribution). The best DFT results are obtained using the M06 functional with mean absolute deviation (MAD) = 0.2 G for the dipole-dipole contribution and MAD = 0.7 G for the contact coupling contribution. In general, vibrational correction significantly improved most DFT functionals' performance but did not change its overall ranking.

A [3Fe–3S]3+ cluster with exclusively μ-sulfide donors

A [3Fe–3(μ-S)]3+ cluster is reported in which each ferric center has a distorted trigonal pyramidal geometry, with an S = 1/2 ground state for the cluster and unusually anisotropic hyperfine coupling constants as determined by variable temperature magnetometry and Mössbauer spectroscopy.

Hyperfine Interactions in Half-Doped and 2/3-Doped Charge-Ordering Manganites

The present work is devoted to the theoretical interpretation of nuclear magnetic resonance (NMR) spectra on nonmagnetic lanthanum ion in charge-ordered La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3 compounds. It is shown that the anisotropic hyperfine interaction, which arises due to the polarization of lanthanum’s external p-shells, plays a crucial role in spectrum forming. Our model allows to explain experimental spectra. The work is partially supported by CRDF REC-005.