th  - 1987 - 51st ENC Conference

Tuesday - PM
SUPPRESSION OF DIPOLAR BROADENING BY MAGIC ANGLE SPINNING
Robert A. Wind, Steven F. Dec and Gary E. Maciel
Department of Chemistry
Colorado State University
Fort Collins, CO 80523
We have developed a Magic Angle Spinning system that operates over a
large range of rotor diameters and corresponding rotor velocities, the
latter reaching a maximum of 85% of the velocity of sound with air as a
driving gas, and a maximum of 105% of the velocity of sound (in air)
using a combination of He and air as driving gases. A spinning system
with a 4.5-mm o.d. rotor, which can be rotated at a frequency of up to 23
kHz, has been used to investigate the line-narrowing possibilities of
abundant-spin spectra in solids via MAS. Results will be shown of 1H and
19F spectra of a variety of solid compounds with static linewidths
varying from 12 to 30 kHz. The residual linewidths obtained as a func-
tion of spinning speed will be discussed, and the prospects of obtaining
chemical shift information from the narrowed spectra will be considered.
Finally, results will be shown of 13C spectra obtained via cross polari-
zation at high spinning speeds.