Improved estimation of CSA-dipolar coupling cross-correlation rates from laboratory-frame relaxation experiments.
We have investigated the underlying assumptions in estimating cross-correlation rates between chemical shift anisotropy (CSA) and dipolar coupling mechanisms in a scalar-coupled two-spin IS system, from laboratory frame relaxation experiments. It has ben shown that for an arbitrary relaxation delay, the difference in relaxation rates of the individual components of an in-phase (or antiphase) doublet is not related to the CSA-dipolar coupling cross-correlation rate in a simple way. This is especially true in the case where the difference in the decay rates of the in-phase and antiphase terms of the density matrix becomes comparable to the magnitude of the scalar coupling between the two spins. Improved means of extracting cross-correlation rates in these cases are presented.
Ghose
R
R
Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
Prestegard
J H
JH
D016880:Anisotropy; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008433:Mathematics; D008962:Models, Theoretical; D011506:Proteins / Q000737:chemistry; D013113:Spin Labels
D011506:Proteins; D013113:Spin Labels