The theoretical approach utilizing bimodal Floquet theory in the quadrupolar/central-transition interaction frame, presented in an earlier article [J. D. Walls, K. H. Lim, and A. Pines, J. Chem. Phys. 116, 79 (2002)], is extended to describe the more complicated spin dynamics of I=5/2 spin systems. Rotary resonance effects occur when the strength of the radio-frequency irradiation, omega(1), matches the sample spinning speed, omega(r), at the conditions omega(1) = 2/3nomega(r) (n integral). At these conditions, conversions of both triple-quantum and five-quantum coherences to central-quantum coherence are observed. Between rotary resonance conditions [ 2n/3omega(r)\<ω(1)\<[2(n+1)]/3ω(r)], five-quantum as well as triple-quantum coherences can be created from equilibrium z-magnetization via a nutation mechanism. In addition, effective transfer between five-quantum and triple-quantum coherences also is observed in between rotary resonance conditions. These effects have been investigated theoretically and verified by both numerical calculations and experimental results. (C) 2002 American Institute of Physics.

}, keywords = {SPECTROSCOPY}, isbn = {0021-9606}, doi = {Doi 10.1063/1.1483256}, url = {A theory of the spin dynamics of I=3/2 quadrupolar nuclei in the sudden-passage limit is discussed in relation to the recently observed rotational resonance (RR) effects on the excitation and conversion of triple-quantum coherence in the FASTER multiple-quantum magic-angle spinning (MQMAS) experiments [T. Vosegaard, P. Florian, D. Massiot, and P. J. Grandinetti, J. Chem. Phys. 114, 4618 (2001)]. A novel interaction frame, which combines the quadrupolar interaction with the central transition radio frequency irradiation, is shown to be useful in understanding the complex spin dynamics at and away from RR conditions. Analytical expressions for the Hamiltonian obtained from bimodal Floquet theory are included in order to provide insight into the spin dynamics observed in the FASTER MQMAS experiments. Numerical simulations have been performed and were found to support the theoretical formalism. (C) 2002 American Institute of Physics.

}, keywords = {solids}, isbn = {0021-9606}, doi = {Doi 10.1063/1.1421613}, url = {