ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Iterative schemes have been used in NMR to generate pulse sequences which excite spin systems over narrow or broad ranges of transition frequencies and radio frequency amplitudes. Mathematical methods employing iterative maps and related concepts from nonlinear dynamics have been applied in the analysis of these schemes. The effect of transforming a pulse sequence by an iterative procedure can be represented as an iterative map on a quantum statistical propagator space, with fixed points in this space corresponding to certain desired responses of the spin system. The stability of these points with respect to variations of parameters, such as amplitudes or energies, determines the bandwidth characteristics of the corresponding sequence; broadband behavior results from stable fixed points, and narrowband behavior from unstable fixed points. This paper examines schemes which produce maps with more than one stable fixed point. Such schemes are shown to generate sequences which exhibit bistable or selective, bandpass behavior. Spatially selective NMR, spin decoupling, nk-quantum selective multiple-quantum NMR, isotope selective zero-field NMR, and optical information storage are some of the applications which can benefit from bandpass selective excitation sequences.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.452020
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