Department of Chemistry, University of Alberta        March 2006
NMR News 2006-02
News and tips from the NMR support group for users of the Varian NMR systems in the Department

There are no fixed publishing dates for this newsletter; its appearance solely depends on whether there is a need to present information to the users of the spectrometers or not.

Other content of this NMR News is no longer meaningful and has been removed May 2010.



changes in default parameters in EZ NMR


information on how to set up and use remote NMR data processing (for PCs and Macs)


information about NMR data processing with third party software


Changes in default parameters in EZ NMR
Increased data storage capacity and much faster computers compared to a few years ago, make it possible to increase the number of data points np  (and consequently the acquisition time at). Together with higher values for fn (Fourier number) this results in larger data files but with better digital resolution (dres) as a noticeable benefit, especially in 2D spectra. The changes are made in such a way that the total relaxation (d1+at) remains unchanged. The new default values are as follows:



d1 [sec] at [sec] np fn dres
[Hz/pt] (2)

CDCl3, C6D6, CD2Cl2, DMSO, Acetone-D6

0.1 5.0 36,000 (i300)
72,000 (i600)
128K 0.06

D2O, CD3OD (1)

2.0 3.0 21,600(i300)
43,200 (i600)
128K 0.06

(1) efficient suppression of the residual solvent peak without using too much power requires at least a 2:3 ratio of d1 (when the decoupler is on) vs. at (when the decoupler is off). This is preferable over increasing the decoupler power which leads to attenuation, possibly full suppression, of peaks close to the solvent signal.
(2) dres depends on fn not np, the ratio fn/np is known as zero-filling



d1 or
satdly [sec]
at [sec] np fn dres in F2 [Hz/pt] (2)

all solvents

1.0 1.0 7,200 (i300)
14,400 (i600)

(3) u500, ibd5 and i600: fn = 16K resulting in 0.7, 0.7 and 0.9 Hz/pt digital resolution, respectively; i300, i|m|s400: fn = 8K resulting in 0.9 and 1.2 Hz/pt digital resolution, respectively

As a remainder, fn cannot be set to any number like np, only multiples of 2 are possible. This entails slightly different values for dres at different fields (= different sweep widths!).

Information on how to set up and use remote NMR data processing (for PCs and Macs)
Several documents in PDF form are available to set up remote access to the NMR server for data processing. Please note that no matter what you plan to do, the computer must be inside the Department and has to pass a security check by our IT group before access is granted. The PDF files are available with detailed information: for PCs and for Macs (setup for Mac, instructions on how to use once set up for the Mac).

Thanks to Doug Burr in Dr. Vederas' research group for providing the information for the Mac computers.

Information about NMR data processing with third party software
Data processing in the Department is done in two different ways: (1) use of one of the NMR data stations or spectrometers, (2) remote access to the d601 or ibdw server from a Mac of PC (see above). Occasionally, there are users who do not like this approach and instead prefer to use different software installed on their own computer(s). Without a doubt, there are many software packages available, either as freeware or for purchase. Links to two software packages have been added to the Links page.

The NMR support group does not provide help and support for any such packages but certainly does not want to hold anyone back from working with NMR software other than VNMRJ. The most common advantage of such software packages seems to be the ability to create spectra for easy inclusion in reports and publications. As a reminder this can be done in VNMR by printing to a file in postscript format. After that there is virtually no limit on what can be done with the file inside a program like, for example, Corel Draw. One important point: inside the NMR data system, data are backed up daily. Whatever you put on your own computer is, of course, no longer part of this safe-guard against data loss, in other words it becomes entirely your responsibility. 

top of page    NMR News