HARDWARE: *AM500
*5mm inverse probe, using the transmitter
cable into the X-channel (tuned to 113Cd,
~110MHz at 11.7T).
SAMPLE: *0.7M Cd(ClO4)2, natural abundance 113Cd -->
ca 100mM 113Cd.
I had just gotten through tuning up the 113Cd side of the probe
and I wanted to take a simple pulse-acquire 1D cadmium spectrum.
To make a long story short, it turned out that changing the O1
setting (and doing either a ZG or an II to commit the O1 change)
would affect the deuterium lock signal rather significantly. To
be more specific, I observed a sinusoidal oscillation in the lock
signal (whether the machine was actually running locked or
unlocked). The frequency and amplitude of this oscillation was
highly dependent on the O1 setting; the largest effect was observed
when the O1 was placed on the 113Cd peak, and the effect was
still noticeable to within +/- 10Hz of this signal. Note that I
was not sending any rf pulses to the probe at any time in any way
Hmmm. Fundamentally, I find this whole thing rather
disturbing, as it suggests an interaction between the lock &
transmitter channels. Can anyone comment on this?
Thanks in advance,
Kevin
-- ************************************************************************* Kevin Gardner Yale University Dept. of Molecular Biophysics and Biochemistry Internet: gardner@zinc.csb.yale.edu Bitnet: gardner@yalemed