Elsevier, Chemical Physics Letters, 1-2(146), p. 71-76
DOI: 10.1016/0009-2614(88)85051-6
Full text: Unavailable
In magic angle spinning experiments, on samples containing dilute homonuclear dipolar-coupled spin pairs, rotational resonance occurs when the spinning speed is adjusted so that the condition ωδiso=nωr is satisfied. Here ωδiso is the difference isotropic chemical shifts, ωr is the spinning speed, and n is an integer. Under these conditions the normally sharp resonance lines broaden and split. In addition, a rapid oscillatory exchange of Zeeman order between the dipolar-coupled spins is observed. The time dependence of the exchange and the spectral lineshapes agree with numerical simulations. The method is potentially useful for estimating through-space dipolar couplings, and therefore internuclear distances in polycrystalline solids.