Hello,
I have a question about SWH or SW_h parameter in XWINNMR (version 1.3
on ARX-400 instrument). When I print acquisition parameters for my
standard 13C spectrum SWH = 25000.000 Hz but if I check in the acqus
file SW_h = 26315.789 (is this the same parameter?).
We discovered that discrepancy while trying to process Bruker data using
JEOL's DELTA software and obtaining chemical shift values about 5%
larger than those recorded by XWINNMR processing. JEOL application
people observed that changing SW_h in acqus file to the "printed" SWH
value fixes the chemical shift problem. The same effects are observed
for ACD or NUTS processing.
And now, the most confusing part: if I open the same data set using
XWINNMR and enter eda command: SWH = 20000 Hz. Another value!
I don't have much experience with Bruker spectrometers and XWINNMR and I
am now completely confused. Can anybody explain to me the meaning of
these parameters: SWH and SW_h, if they are not the same thing? How can
I force SW_h = SWH if it is necessary for correct processing by DELTA
and other programs? In other words: what is wrong with my acquisition
and/or processing parameters?
Thank you for your help,
Piotr
Piotr Dobrowolski, Ph.D.
NMR/EPR Manager
Department of Chemistry and Biochemistry
Utah State University
0300 Old Main Hill, Logan UT 84322-0300
telephone: (435) 797-1673
fax: (435) 797-3390
http://www.chem.usu.edu/pages/facilities/nmrfacility.html
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