P. Reinheimer et al., CROSS-POLARIZATION DYNAMICS AND PROTON DIPOLAR LOCAL-FIELD MEASUREMENTS IN SOME ORGANIC-COMPOUNDS, Magnetic resonance in chemistry, 35(11), 1997, pp. 757-764
Hartmann-Hahn inversion-recovery cross-polarization magic-angle spinni
ng experiments were performed for all types of protonated carbons (CHn
with n = 1, 2 and 3), The resulting non-exponential decays were analy
zed using both a simple memory function approach and density matrix ca
lculations. Although the memory function approach provides a useful an
alytical description of the cross-polarization dynamics, the density m
atrix method is required to account better for the details of the spin
dynamics. C-13-detected dipolar local fields of protons were measured
using the wideline separation experiment, It was observed that the re
sulting local free induction decays may be quantitatively described by
their local second moment. Moreover, the local spin diffusion process
controlling the second stage of the cross-polarization dynamics is di
rectly related to the strength of the local dipolar field of protons.
(C) 1997 John Wiley & Sons, Ltd.