Info For Group Members

Homodecoupled ¹H spectra

rpar std1hhd
set PL14 120
choose desired SW, AQ, D1. Record normal spectrum, correct phasing. Since the receiver is turned on and off during acquisition to allow homonuclear decoupling, the signal to noise ratio is much worse than in normal experiments. Don't be surprised.
Copy the parameters to a new experiment with edc
Decide which signal you want to decouple and set O2P to the desired frequency in ppm.
Choose the power of the decoupling pulse, typically PL14 70, never smaller than 54. Setting pl14 to 120 means no power at all. Decreasing this number increases the power of the decoupling pulse by a factor of 2 for approx. 6db. Never ever use a value less than 54, since this might damage the probe head!!
record the spectrum using normal zg - efp sequence. The decoupled peak should more or less vanish.
Adjust PL14 and O2P until the optimal result is obtained. Never set PL14 smaller than 54!. You could also play around with AQ and D1.
In my experience the best results are obtained with small AQ (0.5s), no D1 (0), NS > 8 and O2P set 0.01 ppm upfield of the desired peak. It will not be possible to decouple broad multiplets or even triplets with big coupling constants completely.
For complicated spin systems and/or overlapping peaks, record one spectrum with identical settings, but PL14 120 and O2P 15, and use the DUAL DISPLAY mode to recognize changes in the spectrum.