th  - 1988 - 51st ENC Conference

TUE 9"20 ]
2D ROTATING FRAME SPECTROSCOPY NEW APPROACHES AND PROSPECTS: C.
Griesinger, C. SchOnenberger, R. Briischweiler, W.O. Scrensen, and R.R. Ernst,
Laboratorium fiir Physikalische Chemie, EidgenOssische Technische Hochschule,
8092 Ziidch, Switzerland
The general potential of rotating frame spectroscopy is explored in view of the
elucidation of structure and the study of molecular dynamics. Cross relaxation,
coherence transfer, as well as spectral features in the rotating frame show
properties distinct from those in the laboratory frame that can be exploited for
molecular studies. Several techniques have been described so far that involve
rotting frame concepts. In this lecture, a unified treatment of rotating frame
experiments is applied and new sequences with improved performance are
presented.
It is known that the standard techniques of rotating frame spectroscopy suffer
from interference of coherent and incoherent transfer processes. New types of
mixing sequences allow the exclusive selection of a single mechanism. This can lead
to a more accurate quantification of transfer rates. The new approaches are
illustrated by application to biomolecules.
The potential of more exotic rotating frame techniques is discussed.
Experiments involving transfer of higher spin order in the rotating frame or
frequency-selective spin locking are conceivable. The incorporation of rotating
frame and laboratory frame sequences into 3D expcriments will be illustrated by
protein spectra.
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