Log X2 Distribution of Correlation Times Revisited
MISSOURI UNIV-ROLLA DEPT OF CHEMISTRY
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The log-X2 distribution of correlation times and its application to polymer systems are examined. It is found that the original mean correlation- time parameter, T sub o, Macromolecules, 1973, 6, 882 does not represent the true mean of the distribution. A properly parameterized log 2 distribution and function relating the original T sub o and width parameters, p and b, to the true mean are derived. Fitting of both the original log-X2, corrected log-X2, and log-normal distribution to experimental data is discussed and the log-normal distribution being proposed as an alternative. Interpretations of NMR data from polymersolvent systems can be different for the log-X2 and lognormal distributions. Due to its better defined moments, the log-normals results are believed to be more physically realistic when large widths are required. NMR, Polymers, Molecular motion, Dynamics, Correlation times.
- Polymer Chemistry
- Atomic and Molecular Physics and Spectroscopy