Decoupling and recoupling using continuous-wave irradiation in magic-angle-spinning solid-state NMR:A unified description using bimodal Floquet theory

摘要

The application of two or more different time-dependent coherent perturbations with,in general,incommensurable frequencies occurs quite commonly in NMR experiments.Here we develop a unified description of the entire class of experiments using bimodal Floquet theory and van Vleck-Primas perturbation theory.This treatment leads to a time-independent effective Hamiltonian in Hilbert space and can be looked at as a generalization of average Hamiltonian theory to several incommensurate time dependencies.As a prototype experiment we treat the application of continuous-wave(cw)radio-frequency irradiation in combination with magic-angle sample spinning.Practically relevant examples of this type of experiments are heteronuclear spin decoupling and recoupling experiments using cw irradiation,e.g.,rotary-resonance recoupling.Perturbations up to the third order must be taken into account to explain all experimentally observed resonance conditions.? 2005 American Institute of Physics.[DOI:10.1063/1.1944291]