M. Eden et L. Frydman, Quadrupolar-driven recoupling of homonuclear dipolar interactions in the nuclear magnetic resonance of rotating solids, J CHEM PHYS, 114(9), 2001, pp. 4116-4123
We discuss the recoupling of homonuclear dipolar interactions between quadr
upolar nuclei under magic-angle spinning conditions, caused by the first-or
der quadrupolar interaction. This recoupling leads to NMR linewidths displa
ying a nonmonotonic dependence on the spinning frequency, meaning that broa
der lines may result as the spinning rate is increased. The effect depends
on geometrical parameters of the spin system, which makes it suitable for d
istance measurements and for obtaining the relative orientations of dipolar
and quadrupolar tensors. We propose a theoretical model of the dipolar rec
oupling based on average Hamiltonian theory, and find it in good agreement
with numerically exact simulations and experiments on I=3/2 systems. (C) 20
01 American Institute of Physics.