th  - 1987 - 51st ENC Conference

MF3- POSTERS
NMR SPECTROSCOPY BELOW 1K
Oded Gonen*, P. Kuhns, P. C. Hammel and J. S. Waugh
Department of Chemistry
Massachusetts Institute of Technology
Cambridge, Massachusetts 02139
L. Boltzmann tells us that large (>104 ) gains in NMR sensitivity can be
obtained by lowering the temperature to ~YbBo/k, a few millikelvin. We will
present a selection of results obtained in pursuit of this goal, to illustrate
the following points:
>T1, previously expected to be astronomically large, is quite acceptably
short in powdered samples immersed in liquid 3He.
>Signals are indeed large: sometimes nearly a volt directly from the
probe. Monolayers of adsorbed species give strong spectra in a single shot.
mometer.
>The shape of the spectrum provides a convenient self-calibrating ther-
>The usual FT relation between the FID and the spectrum is modified at
low temperatures.
>Spin-spin relaxation is sometimes anomalously slow.