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Frequently Asked Questions

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Auto gain fails with "Gain driven to 0" message
My sample is not spinning
How do I access my data remotely?
What software can I use to access my data remotely?
Can I process my NMR data on my personal computer?
What book(s) should I read to learn more about NMR?

Auto gain fails with "Gain driven to 0" message

The most common cause of this error is very high sample concentration. The solution is to use pulses with flip angles much smaller than the usual 45 degrees. In order to do that reduce the transmitter power by typing:
tpwr=tpwr-3[rtn]
and run the experiment again. Keep lowering tpwr until the error message disappears.
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My sample is not spinning

Put the standard back into the magnet and see if it will spin. If the standard fails to spin, notify the facility staff, and we will look into it as soon as we can.
If the standard does spin, the problem is most likely with your sample tube. J Young tubes (which you should not spin anyway) may have trouble spinning beacuse they are top heavy. Cheap tubes (2XX, 505) are often not straight (there is reason they are cheap) and rub against the glass insert in the probe, which produces enough friction to prevent spinning. In the worst case, they can break inside the probe. The solution is to transfer your sample to a good tube and throw the bad one away.
Occasionally, even expensive tubes (wilmad 528, 535 or equivalent) will bend, especially if you store them standing upright in a flask in an oven.
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How do I access my data remotely?

If you have an internet connection you can get to your files from any computer using a secure ftp client. Connect to our server nmrnet.chem.cornell.edu using your usual username and password. Your data is located in the /data/username folder.
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What software can I use to access my data remotely?

You can use any secure ftp client to access your data. Traditional, non-secure ftp connections are not allowed on our server.
For remote access we recommend the following secure ftp clients.
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Can I process my NMR data on my personal computer?

There are a number of free programs for processing NMR spectra on personal computers.
Windows PCs

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What book(s) should I read to learn more about NMR?

In my (Ivan) oppinion, the best book on practical NMR spectroscopy is High resolution NMR Techniques in Organic Chemistry by Timothy D. Claridge (Pergamon, 1999). The book is available from Amazon.com in softcover for $47. You can also borrow it from me if you want a preview.
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Spectrometers: | Mercury 300 | AV400 | INOVA 500 | AV500 | AV501 | INOVA 600
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Questions, concerns, comments? Contact Ivan Keresztes, B-54, 255 0709, ik54@cornell.edu