NMR-Related Operating Instructions

A note about changing the spectral window (sw) in an NMR experiment

You will likely be needing to change the spectral window for various NMR experiments and the movesw command allows you to easily set the desired spectral window interactively.

For instance, suppose you suspected that you had some resonances shifted outside the ppm range of that provided with the standard parameter set (for instance, a carboxylic acid OH). A simple and quick way to set the appropriate window would be to run a one-scan spectrum with a very large spectral window, then use the movesw command, interactively, to set the desired window.

  1. Set sw to a very large number, say 30,000Hz (type sw = 30000). This will ensure that the window is large enough to include the unusually shifted peaks.
  2. Take a quick 1-scan spectrum. Locate the peaks of interest and expand the window around the window of interest.
  3. With the correct window displayed, type movesw, and the sw (and tof) gets set to the proper window.

When doing a 2D NMR experiment, it is generally best to make the spectral window as small as possible -- just big enough to include all the peaks of interest. Again, use the movesw command to set the proper window.