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Molecular Liquids and Polymers Investigated by Field Cycling 1H NMR Relaxometry: Impact of Rotational and Translational Dynamics on Relaxation
| Content Provider | Semantic Scholar |
|---|---|
| Author | Meier, Roman |
| Copyright Year | 2014 |
| Abstract | Field cycling (FC) H NMR relaxometry has been applied to study translational and rotational dynamics of nondeuterated (-h8) and partially deuterated (-h3 and -h5) glycerol in a broad temperature range. We demonstrate that a low-frequency excess intensity observed in the relaxation dispersion stems from intermolecular dipole-dipole interactions mediated by translational dynamics, whereas the main relaxation is attributed to rotational dynamics. A theoretical description of the relaxation processes is formulated accounting for H-H as well as H-H relaxation channels for the partially deuterated systems. While the intermolecular spectral density is derived from the force-free-hard-sphere model (Fick diffusion with appropriate boundary conditions) of translational motion, the intramolecular relaxation contribution is described by a Cole-Davidson spectral density. This ansatz reproduces very well the dispersion profiles obtained from FC H NMR. Moreover, the approach allows extracting the diffusion coefficient D, which is in good agreement with results from gradient H NMR. Thus, H NMR relaxometry has the potential to become an alternative method for measuring the diffusion coefficient in viscous liquids. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://epub.uni-bayreuth.de/1691/1/manuscript_final.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
