Talk:Earth's field NMR

Stub Article
I requested an article on this subject some time ago (on NMR Talk page), but without result. This is a stub article that I hope will get the ball rolling. I have only an outline knowledge of the subject, and of Wikipedia editing, which I will study when I can. Technical input and re-formatting requested - welcomed. GilesW 13:01, 26 May 2007 (UTC)

Context
It is hard to know where to begin and end an introduction to this topic. Most people will access this from the link contained in the NMR article, which should provide more than enough context. I will mention this. GilesW 13:01, 26 May 2007 (UTC)
 * Context added. Is that better? GilesW 11:42, 5 August 2007 (UTC)

Disambiguation or redirection
Please review and fix if desirable. Electric field NMR is much less widely used than Earth's field NMR.GilesW 06:09, 31 May 2007 (UTC)

Pictures requested
These machines are less expensive, less power consuming, and smaller than the ones with the large Tesla constant magnetic fields. University and college chemical analysis labs must have them. Someone from one of these places could use a tripod and take some digital photos of the units from a couple of angles and have a person standing in frame for some perspective of the scale involved, similar in the way that the main NMR article has done with the two bigger machines pictured. Oldspammer 18:31, 26 July 2007 (UTC)


 * Link to illustration on an external website added. Is this OK? Other suitable links welcome. GilesW 10:06, 5 August 2007 (UTC)


 * Cheaper— sure. But still too expensive for a toy. It is still unclear if useful new science can be done on most of these instruments. --68.238.164.208 (talk) 06:09, 20 April 2009 (UTC)

DIY project

 * Re the above: Whereas sophisticated commercial equipment is too expensive for individual hobbyists, DIY data and designs for basic proton precession magnetometers are available that are within the capability of reasonably competent electronic hobbyists to build, for a few tens of pounds. e.g. Google found me [] and []. Article updated accordingly. GilesW (talk) 21:38, 7 August 2009 (UTC)

Propose change to Introduction re spin-spin coupling
Revise final para of intro something like this:

The location of a nucleus within a complex molecule affects the 'chemical environment' (i.e. the rotating magnetic fields generated by the other nuclei) experienced by the nucleus. Thus different hydrocarbon molecules containing NMR active nuclei in different positions within the molecules produce slightly different patterns of resonant frequencies. Whereas chemical shifts are important in NMR, they are insignificant in the Earth's field. Instead, EFNMR spectra are dominated by spin-spin coupling (J-coupling) effects, which provide useful information about the molecules in the sample. The absence of chemical shifts causes features such as spin-spin multiplets (that are separated by high fields) to be superimposed in EFNMR, complicating the analysis of the resulting spectra.

EFNMR signals are sensitive to magnetically noisy environments. Historically this has reduced the usefulness of EFNMR as a laborotory tool. Recent developments include electronic compensation for changes in the ambient magnetic field, which can enhance the usefulness of EFNMR in the laborotory.

Any suggestions? GilesW (talk) 13:16, 29 June 2011 (UTC)