Asymmetry in three-site relaxation exchange NMR
<p>The asymmetry of peak integrals in 2D relaxation maps of exchange between three sites indicates circular flow between the relaxation sites. This disagrees with the detailed balance according to which the exchange between any pair of sites must be balanced in terms of thermodynamic equilibri...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-08-01
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| Series: | Magnetic Resonance |
| Online Access: | https://mr.copernicus.org/articles/4/217/2023/mr-4-217-2023.pdf |
| _version_ | 1797737601332936704 |
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| author | B. Blümich M. Parziale M. Augustine |
| author_facet | B. Blümich M. Parziale M. Augustine |
| author_sort | B. Blümich |
| collection | DOAJ |
| description | <p>The asymmetry of peak integrals in 2D relaxation maps of exchange between three
sites indicates circular flow between the relaxation sites. This disagrees
with the detailed balance according to which the exchange between any pair of
sites must be balanced in terms of thermodynamic equilibrium. Confined diffusion of
particles jumping randomly on a 2D checkerboard grid to any of their eight
neighbor positions and confined gas diffusion were modeled in Monte Carlo
simulations to explore the impact of topological constraints on particle
exchange between three pools. Both models produce density variations across
the pore and reveal that up to 1 % of the molecules move in circular paths
between the relaxation pools. This motion is driven by different features of
either algorithm. It is silent in terms of thermodynamic equilibrium, confirming that
multi-site exchange maps are symmetric in this case. The coherent flux is
argued to result from stochastic pore resonance related to diffusion
eigenmodes. If it can be driven experimentally by external time-varying
electric, magnetic, or ultrasonic fields, this may be a way to enhance
heterogeneous catalysis.</p> |
| first_indexed | 2024-03-12T13:31:44Z |
| format | Article |
| id | doaj.art-b8915a0bc9b1414da40a9f63b32a9c1a |
| institution | Directory Open Access Journal |
| issn | 2699-0016 |
| language | English |
| last_indexed | 2024-03-12T13:31:44Z |
| publishDate | 2023-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Magnetic Resonance |
| spelling | doaj.art-b8915a0bc9b1414da40a9f63b32a9c1a2023-08-24T11:29:08ZengCopernicus PublicationsMagnetic Resonance2699-00162023-08-01421722910.5194/mr-4-217-2023Asymmetry in three-site relaxation exchange NMRB. Blümich0M. Parziale1M. Augustine2Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringer Weg 2, 52074 Aachen, GermanyDepartment of Chemistry, UC Davis, One Shields Avenue, Davis, CA 95616, USADepartment of Chemistry, UC Davis, One Shields Avenue, Davis, CA 95616, USA<p>The asymmetry of peak integrals in 2D relaxation maps of exchange between three sites indicates circular flow between the relaxation sites. This disagrees with the detailed balance according to which the exchange between any pair of sites must be balanced in terms of thermodynamic equilibrium. Confined diffusion of particles jumping randomly on a 2D checkerboard grid to any of their eight neighbor positions and confined gas diffusion were modeled in Monte Carlo simulations to explore the impact of topological constraints on particle exchange between three pools. Both models produce density variations across the pore and reveal that up to 1 % of the molecules move in circular paths between the relaxation pools. This motion is driven by different features of either algorithm. It is silent in terms of thermodynamic equilibrium, confirming that multi-site exchange maps are symmetric in this case. The coherent flux is argued to result from stochastic pore resonance related to diffusion eigenmodes. If it can be driven experimentally by external time-varying electric, magnetic, or ultrasonic fields, this may be a way to enhance heterogeneous catalysis.</p>https://mr.copernicus.org/articles/4/217/2023/mr-4-217-2023.pdf |
| spellingShingle | B. Blümich M. Parziale M. Augustine Asymmetry in three-site relaxation exchange NMR Magnetic Resonance |
| title | Asymmetry in three-site relaxation exchange NMR |
| title_full | Asymmetry in three-site relaxation exchange NMR |
| title_fullStr | Asymmetry in three-site relaxation exchange NMR |
| title_full_unstemmed | Asymmetry in three-site relaxation exchange NMR |
| title_short | Asymmetry in three-site relaxation exchange NMR |
| title_sort | asymmetry in three site relaxation exchange nmr |
| url | https://mr.copernicus.org/articles/4/217/2023/mr-4-217-2023.pdf |
| work_keys_str_mv | AT bblumich asymmetryinthreesiterelaxationexchangenmr AT mparziale asymmetryinthreesiterelaxationexchangenmr AT maugustine asymmetryinthreesiterelaxationexchangenmr |