Theoretical investigations of IÄ5Õ2 quadrupolar spin dynamics in the sudden-passage regime

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 I55/2 spin systems. Rotary resonance effects occur when the strength of the radio-frequency irradiation, v1 , matches the sample spinning speed, vr , at the conditions v15 2 3nvr ~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 3 vr,v1,@2(n11)#/3 vr# , 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. © 2002 American Institute of Physics. @DOI: 10.1063/1.1483256#