Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 34: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 34.9: Vortrag

Donnerstag, 4. April 2019, 12:30–12:45, H44

Computation of NMR shifts for paramagnetic solids including zero-field-splitting: significant effects beyond the contact shifts — •Arobendo Mondal^1,2 and Martin Kaupp¹ — ¹Theoretical Chemistry/Quantum Chemistry, TU Berlin, Germany — ²Theoretical Chemistry, TU Munich, Germany

NMR is a powerful tool for studying the structural and electronic properties of paramagnetic solids. However, the interpretation of para-magnetic NMR spectra is often challenging as a result of the interactions of unpaired electrons with the nuclear spins of interest. Recently, we reported a novel protocol to compute and analyze NMR chemical shifts for extended paramagnetic solids, accounting comprehensively for Fermi-contact (FC), pseudo-contact (PC), and orbital shifts.^[1] We combine periodic DFT computation of hyperfine and orbital-shielding tensors with an incremental cluster model for g- and zero-field-splitting (ZFS) D-tensors. The hyperfine tensors are computed with hybrid DFT functionals using the highly efficient Gaussian-augmented plane-wave implementation of the CP2K code. The incremental cluster model allows the computation of g- and ZFS D-tensors by ab initio complete active space self-consistent field and N-electron valence-state perturbation theory methods. We find that ⁷Li shifts in the high-voltage cathode material LiCoPO₄ are dominated by spin-orbit-induced PC contributions, in contrast to previous assumptions, changing the interpretation of the shifts fundamentally in terms of covalency.

[1] Mondal, A.; Kaupp, M. J. Phys. Chem. Lett., 2018, 9, 1480-1484.