On December 16, 2021, Becher, M.; Koerber, Th.; Doess, A.; Hinze, G.; Gainaru, C.; Boehmer, R.; Vogel, M.; Roessler, E. A. published an article.Formula: C13H10O3 The title of the article was Nuclear Spin Relaxation in Viscous Liquids: Relaxation Stretching of Single-Particle Probes. And the article contained the following:
Spin-lattice relaxation rates R1(ω,T), probed via high-field and field-cycling NMR (NMR), are used to test the validity of frequency-temperature superposition (FTS) for the reorientation dynamics in viscous liquids For several liquids, FTS is found to apply so that master curves can be generated. The susceptibility spectra are highly similar to those obtained from depolarized light scattering (DLS) and reveal an excess wing. Where FTS works, two approaches are suggested to access the susceptibility: (i) a plot of deuteron R1(T) vs the spin-spin relaxation rate R2(T) and (ii) a plot of R1(T) vs an independently measured reference time τref(T). Using single-frequency scans, (i) allows one to extract the relaxation stretching as well as the NMR coupling constant Surveying 26 data sets, we find Kohlrausch functions with exponents 0.39 < βK ≤ 0.67. Plots of the spin-spin relaxation rate R2-rescaled by the NMR coupling constant-as a function of temperature allow one to test how well site-specific NMR relaxations couple to a given reference process. Upon cooling of flexible mol. liquids, the site-specific dynamics is found to merge, suggesting that near Tg the mols. reorient essentially as a rigid entity. This presents a possible resolution for the much lower stretching parameters reported here at high temperatures that contrast with the ones that were reported to be universal in a recent DLS study close to Tg. Our anal. underlines that deuteron relaxation is a uniquely powerful tool to probe single-particle reorientation. The experimental process involved the reaction of Phenyl Salicylate(cas: 118-55-8).Formula: C13H10O3
The Article related to viscous liquid nuclear spin lattice relaxation stretching kohlrausch function, Magnetic Phenomena: Nuclear Resonances and other aspects.Formula: C13H10O3
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics