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Thursday, November 15, 2007

Zero Filling

Zero filling is a data processing technique where zero points are appended to the free induction decay before Fourier transformation. The effect of zero filling is to increase the digital resolution in the spectrum. Since the zeros contain no new information, there is no new information added to the spectrum. You can think of it as artificially increasing the acquisition time after the data collection without adding any new information or true resolution to the spectrum.
To zero fill on a Bruker spectrometer, the "si" parameter is increased to a value greater than the number of points collected in the free induction decay. On a Varian spectrometer, the corresponding parameter is "fn".

3 comments:

Anonymous said...

consider adding a comment that the resolution increase is only "apparent". Zero-filling has only a cosmetic effect.

W@hZai said...

Will zero filling affect quantitative NMR results?

Glenn Facey said...

W@hZai,

The integral of an NMR resonance is determined by the first point of the FID. Therefore adding zeroes (Zero filling) at the end of the FID has no effect quantitative results.

Glenn