Resurrection of Crushed Magnetization and Chaotic Dynamics in Solution NMR Spectroscopy
Yung-Ya Lin,
Natalia Lisitza,
Sangdoo Ahn,
Warren S. Warren*
We show experimentally and theoretically that two
readily observed effects in solution nuclear magnetic resonance
(NMR)--radiation damping and the dipolar field--combine to
generate bizarre spin dynamics (including chaotic evolution) even with
extraordinarily simple sequences. For example, seemingly insignificant
residual magnetization after a crusher gradient triggers exponential
regrowth of the magnetization, followed by aperiodic turbulent spin
motion. The estimated Lyapunov exponent suggests the onset of
spatial-temporal chaos and the existence of chaotic attractors. This
effect leads to highly irreproducible experimental decays that amplify
minor nonuniformities such as temperature gradients. Imaging
applications and consequences for other NMR studies are discussed.
Department of Chemistry, Princeton University, Princeton, NJ
08544, USA.
*
To whom correspondence should be addressed. E-mail:
wwarren{at}princeton.edu
