Absolute NMR shielding scales obtained from nuclear spin-rotation constants. Applications to methyl halides

AUCAR, IGNACIO AGUSTÍN

Groningen

Seminario; Molecular Physics & Theoretical Chemistry Meetings; 2022

University of Groningen

In this talk I will introduce a novel theoretical relationship between two molecular spectroscopic parameters: the nuclear spin-rotation tensor from microwave spectroscopy and the nuclear magnetic shielding tensor from NMR spectroscopy. It is well known in our field of research that the non-relativistic “Ramsey-Flygare relation” is the most widely used procedure to obtain semi-experimental nuclear magnetic resonance (NMR) absolute shielding through a correspondence between the NMR shielding (σ) and nuclear spin-rotation constants (M). One of its generalizations to the relativistic framework is known as the M-V model, which we proposed very recently. This model includes terms that have no non-relativistic counterparts and also includes the paramagnetic contribution to the NMR shielding of the nuclei of free atoms. All this ensures that our results fit quite well with those of the four-component calculations (4c). In this presentation I will present both the theoretical aspects that we use to derive this formal relationship, as well as some applications in linear and nonlinear molecules that allow us to confirm our findings.