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Updated: Mar 16, 2026
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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
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Toward an absolute NMR shielding scale using the spin-rotation tensor within a relativistic framework.
I Agustín Aucar1, Sergio S Gomez1, Claudia G Giribet2
1Instituto de Modelado e Innovación Tecnológica, CONICET, and Departamento de Física - Facultad de Ciencias Exactas y Naturales, UNNE, Avda Libertad 5460, W3404AAS, Corrientes, Argentina. gaaucar@conicet.gov.ar.
Physical Chemistry Chemical Physics : PCCP
|August 11, 2016
Summary
New models generalize Flygare's NMR shielding theory by incorporating relativistic effects for heavy atoms. These models improve accuracy by including spin-orbit interactions, crucial for heavy element calculations.
Area of Science:
- Quantum Chemistry
- Computational Chemistry
- Spectroscopy
Background:
- Flygare's model for NMR magnetic shieldings (σ) is influential but fails with heavy atoms.
- Electronic relativistic effects are crucial for accurate calculations involving heavy elements.
- Nuclear spin-rotation (SR) tensors are key to understanding NMR shieldings.
Purpose of the Study:
- To develop generalized models for absolute NMR magnetic shieldings.
- To incorporate relativistic effects and improve upon Flygare's model for heavy atoms.
- To investigate the relationship between NMR shieldings and SR tensors.
Main Methods:
- Proposed three new models generalizing Flygare's approach.
- Utilized four-component relativistic expressions and a two-component relativistic SO-S term.
- Incorporated relativistic corrections and free atom shielding for accuracy.
- Introduced a Spin-orbit due to spin (SO-S) term in the highest accuracy model.
Main Results:
- Successfully applied the new models to halogen-containing linear molecules.
- Demonstrated improved accuracy in calculating NMR magnetic shieldings for systems with heavy atoms.
- Validated the importance of relativistic effects and specific terms like SO-S.
Conclusions:
- The developed relativistic models effectively generalize and improve upon Flygare's theory.
- Accurate NMR shielding calculations for molecules with heavy atoms require relativistic treatments.
- The proposed models offer a more robust framework for computational spectroscopy.
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