Nuclear induction lineshape modeling via hybrid SDE and MD approach.
| Autor: | Niknam M; Department of Chemistry and Biochemistry, University of California Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1059, USA and Center for Quantum Science and Engineering, UCLA, Los Angeles, California 90095-1059, USA., Bouchard LS; Department of Chemistry and Biochemistry, University of California Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1059, USA and Center for Quantum Science and Engineering, UCLA, Los Angeles, California 90095-1059, USA. |
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| Jazyk: | angličtina |
| Zdroj: | The Journal of chemical physics [J Chem Phys] 2023 Sep 28; Vol. 159 (12). |
| DOI: | 10.1063/5.0163782 |
| Abstrakt: | The temperature dependence of the nuclear free induction decay in the presence of a magnetic-field gradient was found to exhibit motional narrowing in gases upon heating, a behavior that is opposite to that observed in liquids. This has led to the revision of the theoretical framework to include a more detailed description of particle trajectories since decoherence mechanisms depend on histories. In the case of free diffusion and single components, the new model yields the correct temperature trends. The inclusion of boundaries in the current formalism is not straightforward. We present a hybrid SDE-MD (stochastic differential equation - molecular dynamics) approach whereby MD is used to compute an effective viscosity and the latter is fed to the SDE to predict the line shape. The theory is in agreement with the experiments. This two-scale approach, which bridges the gap between short (molecular collisions) and long (nuclear induction) timescales, paves the way for the modeling of complex environments with boundaries, mixtures of chemical species, and intermolecular potentials. (© 2023 Author(s). Published under an exclusive license by AIP Publishing.) |
| Databáze: | MEDLINE |
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