NMR shielding in helium-3 atoms modified by gaseous nitrogen and oxygen
| Autor: | Karol Jackowski, Maria Misiak, Piotr Garbacz |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Fermi contact interaction
Magnetic moment 010405 organic chemistry Chemistry General Chemistry Electron 010402 general chemistry 01 natural sciences Molecular physics 0104 chemical sciences Paramagnetism Dipole Helium-3 Electromagnetic shielding Molecule General Materials Science Physics::Chemical Physics |
| Zdroj: | Magnetic Resonance in Chemistry. 58:745-749 |
| ISSN: | 0749-1581 |
| DOI: | 10.1002/mrc.5030 |
| Popis: | Helium-3 nuclear magnetic resonance (3 He NMR) measurements were carried out for the gaseous mixtures of helium-3 with pure nitrogen and synthetic air as the solvents. It was found that 3 He shielding is linearly dependent on solvent density up to approx. 6 mol/L. At higher density of the gaseous solvent, the change of 3 He shielding is nonlinear and especially distinct when helium-3 atoms can interact with two O2 molecules. The interaction with paramagnetic oxygen molecules can induce two kinds of 3 He shielding changes: (1) due to the isotropic Fermi contact interaction and (2) from the dipolar magnetic interaction between unpaired O2 electrons and 3 He nuclear magnetic dipole moment. The two paramagnetic effects in helium-3 shielding cannot be experimentally separated, although for such small molecular objects, they could be presumably modeled by advanced theoretical calculations. |
| Databáze: | OpenAIRE |
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