Correlation Functions in Nuclear Relaxation. I. Analysis of Random Motions from Field Dependence of Relaxation Times

1965 ◽  
Vol 43 (6) ◽  
pp. 1914-1918 ◽  
Author(s):  
J. M. Deutch ◽  
J. S. Waugh
Keyword(s):  
Field Dependence ◽  
Correlation Functions ◽  
Relaxation Times ◽  
Nuclear Relaxation ◽  
Random Motions

A Selective Determination of the Proton Nuclear Relaxation Times of the Alkaloid Vindoline: An Extension via Fourier Transform Measurements

1974 ◽  
Vol 52 (5) ◽  
pp. 829-832 ◽  
Author(s):  
L. D. Hall ◽  
Caroline M. Preston
Keyword(s):  
Fourier Transform ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Nuclear Relaxation ◽  
Transform Method ◽  
Fourier Transform Method ◽  
Selective Determination ◽  
Spin Lattice

A Fourier Transform method has been used to measure the spin–lattice relaxation times of essentially all the protons of the alkaloid, vindoline. It is shown that even for a molecule of this size substantial and potentially useful differences exist in the experimental relaxation times which reflect the degree of crowding of each proton by other protons.

scholarly journals A study of Supported Poly (n-butyl methacrylate) (PBMA) Thin Polymer Films Near the Glass Transition Temperature

2017 ◽  
Vol 14 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Rami Omari ◽  
Gilbert Ayuk
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Correlation Functions ◽  
Relaxation Times ◽  
Surface Relaxation ◽  
Butyl Methacrylate ◽  
Surface Dynamics ◽  
Thin Polymer ◽  
Bulk Relaxation

The glass transition temperature and the surface dynamics of poly (butyl methacrylate) (PBMA) films have been studied using a phase-modulated ellipsometer equipped with a home-built sample cell with temperature controller. Experiments were performed for a range of temperatures, both above and below the glass transition temperature (Tg). In our study the glass transition temperature was obtained by plotting the ellipticity, as a function of temperature using the data from the ellipsometric cooling scan. the correlation functions governing the fluctuations were calculated at each temperature from the time-dependent fluctuations in film thickness as a function of temperature using ellipsometry data collected at 50 Hz frequency. The results indicate that at temperatures well above Tg, the correlation functions obey a simple exponential decay. However, as Tg is approached, the correlation functions are best fitted with a stretched exponential relation, indicating a broad distribution of relaxation times. In addition, the temperature dependence of surface relaxation process has been found to be much weaker compared to the bulk relaxation.

A comparison of the chlorine nuclear relaxation in the dense paramagnetic insulators K2IrCl6 and K2ReCl6

1976 ◽  
Vol 54 (13) ◽  
pp. 1391-1395 ◽  
Author(s):  
Henry M. Van Driel ◽  
Robin L. Armstrong
Keyword(s):  
Relaxation Times ◽  
Nuclear Quadrupole Interaction ◽  
Nuclear Spin Relaxation ◽  
Nuclear Relaxation ◽  
Relaxation Data ◽  
General Validity ◽  
Spin Lattice ◽  
Magnetic Insulators ◽  
Nuclear Quadrupole ◽  
Hyperfine Interaction Parameters

Chlorine spin–lattice (T1) and spin–spin (T2) relaxation times as measured in the dense paramagnetic insulators K2IrCl6 and K2ReCl6 are tabulated. The Moriya theory of nuclear spin relaxation in magnetic insulators is extended to the case where the nuclear quadrupole interaction gives rise to the stationary eigenstates. Explicit expressions for T1 and T2 are derived in terms of the magnetic hyperfine interaction parameters A and B. The theory is tested by a comparison of the parameters deduced from the relaxation data with parameters obtained from spectroscopic experiments. For K2IrCl6, a comparison with recent ENDOR results confirms the general validity of the theory. For K2ReCl6, the only other results available are from an NMR experiment and the overall agreement is even qualitatively unacceptable. However, both experiments do suggest that [Formula: see text] is anomalously large.

Nuclear Relaxation and Slow Diffusive Motions in CaF2 and NaF

1974 ◽  
Vol 29 (2) ◽  
pp. 278-281
Author(s):  
R. Van Steenwinkel
Keyword(s):  
Activation Energy ◽  
Single Crystals ◽  
Formation Energy ◽  
Relaxation Times ◽  
Nuclear Relaxation ◽  
Vacancy Diffusion

Fluorine relaxation times T1Z , T1D and T2 are measured as functions of temperature in single crystals of CaF2 and NaF. Typical quantities like the activation energy for vacancy diffusion and the formation energy of defect pairs are deduced and reported.

Very long nuclear relaxation times of spin polarized helium 3 in metal coated cells

1995 ◽  
Vol 201 (4) ◽  
pp. 337-343 ◽  
Author(s):  
Werner Heil ◽  
Hubert Humblot ◽  
Ernst Otten ◽  
Matthias Schafer ◽  
Reinhard Sarkau ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Nuclear Relaxation ◽  
Spin Polarized ◽  
Helium 3 ◽  
Polarized Helium
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