Thermonicolet Omnic Software User's Guide 6.1 (PDF) - Charles E ...

You can best compare two spectra if they have the same data spacing. If the
spectra were collected using different spacings, you can use this command to
change the data spacing of one spectrum to match the other.
For example, if you search a deresolved library—with a data spacing of 8 cm -1 —to
identify an unknown spectrum with a data spacing of 2 cm -1 , the software will
deresolve the unknown and then do the search. However, your visual comparison of
the unknown spectrum and the best matches from the library will be hindered
because of the difference in data spacing. By changing the data spacing of the
unknown spectrum to 8 cm -1 , you can make a better visual comparison.
In quantitative analysis the data spacing of the sample spectrum must match the
standard spectra used to develop the method. You can use this command to change
the data spacing of a sample spectrum to match the standards before the analysis.
To subtract spectra of different resolutions, change the data spacing of the lower
resolution spectrum to match the higher resolution spectrum. This adds interpolated
data points between existing points in the lower resolution spectrum (zero fills), so
the data points of the spectra line up when you perform the subtraction.
Change the data spacing of spectra
1. Select the spectra.
2. Choose Change Data Spacing from the Process menu.
The Change Data Spacing dialog box appears.
3. Select a data spacing setting from the drop-down list box.
4. Choose OK.
Changing the data spacing of spectra
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You can use this command to see the effect of zero filling in a spectrum.
OMNIC User’s Guide 221