First-principles study on the NMR shielding of transition metal semiconductors

The theoretical calculation of chemical shielding can help us understand the information of nuclear magnetic resonance experiment more deeply. In this work, three different functionals had been used to study the isotropic shielding of various transition metal nuclei. The predicted trend of our theoretical results matched the experi-mental results well. It was found that the large (more than 2000 ppm) variation of measured 93Nb and 51V chemical shifts were mainly determined by the occupied and empty states of d orbitals. Furthermore, the effect of the energy differences between the occupied and empty states of d orbitals had been discussed as well. This work is helpful to understand the sources and differences of chemical shifts of certain nuclei in transition metal semiconductors.