NMR shielding constants and rederivation of accurate magnetic dipole moments of 77Se, 123Te, and 125Te nuclei

Abstract

Ab initio calculations of NMR shielding constants have enabled the re-evaluation of nuclear magnetic dipole moments from the NMR experiment, offering a significant improvement over outdated diamagnetic corrections. Here, we present accurate ab initio NMR shielding constants for selenium and tellurium compounds: 1. Se(CH3)2 and Te(CH3)2, which define the present NMR standards for selenium and tellurium, and 2. water-solvated SeO32− and TeO32− anions, which were originally used to derive magnetic moments of 77Se, 123Te, and 125Te nuclei. All essential contributions affecting the NMR shielding constants—including relativistic effects, electron correlation, and interactions with solvent—are systematically analyzed. Relativistic effects are treated using four-component density functional theory; electron correlation is incorporated at the coupled cluster level; and solvent effects are modeled using both implicit and explicit solvent approaches. New values of magnetic dipole moments based on the ab initio NMR shielding constants for NMR standards Se(CH3)2, Te(CH3)2 were re-derived and the new recommended reference nuclear magnetic dipole moments are μ(77Se) = 0.533 80(3)μN, μ(123Te) = −0.7341(1)μN, and μ(125Te) = −0.8850(1)μN, The newly determined nuclear magnetic moments provide reliable reference values for nuclear physics, particularly for the spectroscopic measurements of magnetic moments in isotopic series.