Collect. Czech. Chem. Commun. 2000, 65, 1537-1558

Plots of the Spin-Lattice Relaxation Time and Nuclear Overhauser Enhancement NMR Values Yielding a Spread Distribution of the Rotational Correlation Time

Jaromír Jakeš

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic


It is shown, that the plots of ω/T1 and NOE × ω/T1 versus -log ω give the distribution of rotational correlation time τ plotted versus log τ and spread by (rather wide) "slit" functions the form and shape of which are independent of the position on the log τ axis. When plotting data at various temperatures, temperature shift factors aT and the plots versus -log (ωaT) should be used. The plots permit to check the data compatibility and are helpful in studying molecular dynamics. Examples of the plots are given. One example stimulated a consideration of the segmental motion dynamics, which showed that the Hall-Helfand distribution is inappropriate for a description of the orientational relaxation of the non-backbone (C-H) bonds in a polymer chain.

Keywords: NMR spectroscopy; Nuclear magnetic resonance; Spin-lattice relaxation; Nuclear Overhauser enhancement; Graphical correlation; Polymer chain segmental motions; Rotational autocorrelation function; Molecular dynamics.

References: 32 live references.