# Optimizing the $U_{eff}$ value for DFT+U calculation of paramagnetic solid-state NMR shifts by double Fermi-contact-shift verification

## TL;DR

This paper introduces a double Fermi-contact-shift verification method to efficiently optimize the $U_{eff}$ parameter in DFT+U calculations for paramagnetic solid-state NMR shifts, improving accuracy and computational efficiency.

## Contribution

The paper proposes a novel double Fermi-contact-shift verification approach to determine the optimal $U_{eff}$ in DFT+U calculations, enhancing efficiency and accuracy.

## Key findings

- Efficient determination of $U_{eff}$ using dual nucleus Fermi-contact shifts.
- Improved accuracy in calculating NMR shifts and related properties.
- Enhanced computational efficiency over traditional methods.

## Abstract

The isotropic chemical shifts can be calculated either by full-electron configuration, or by hybrid functionals, which costs a large amount of computational resources. To save the time, DFT+U could be employed to calculate the isotropic chemical shifts. However, the calculated properties are very sensitive to the Hubbard correction value $U_{eff}$. Here the double Fermi-contact-shift verification approach with DFT+U method is proposed with much higher computational efficiency, that is, simultaneously calculate the Fermi-contact shifts on two nuclei ($^{6}Li$ and $^{17}O$) to predict the optimal $U_{eff}$. The optimal $U_{eff}$ is also helpful to the calculations of quadrupolar coupling constant $C_{Q}$, $g$-factor, band structure and density of states.

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Source: https://tomesphere.com/paper/1907.10276