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Most of the readers arrive here using Google, without knowing me and my blog. Usually they get very angry because they arrive... on the trapping post I wrote 3 years ago! I want to do something to keep them glad... So you want "open source" stuff? Do you know what it really means? Are you ready to compile, test, debug it and add a graphic interface to it? Just because you asked for it, here is a list of available projects. If you know other links, add them into a comment. CCPN NPK matNMR ProSpectND Connjur Newton-NMR nmrproc DOSY Toolbox list of 30+ projects

It rarely happens to find valuable tips about processing on the web. When it happens, it's probably not enough to bookmark the page (it may disappear), copying it is a better idea. Here is the link: http://spin.niddk.nih.gov/NMRPipe/embo/ When you arrive there, scroll down until you find the chapter Some General Tips About Spectral Processing . The focus is on multi-dimensional processing with NMRPipe, but a few concepts are generally applicable indeed. The brief discussion about first-point pre-multiplication is something to bear in mind. You can also find clearly expressed opinions on zero-filling, linear prediction and baseline correction.

Here is a picture I have found on the internet. I have never been in this place, if this is what you want to hear. Suppose, instead, that I live just in front of this tower and tomorrow I take a photo of it immediately after dawn, then another photo after 25 hours and so on for a week, with regular intervals of 25h between pictures. Eventually I print all the pictures in order and ask you: "This pictures have been taken in this exact order at regular intervals. Can you tell me how long the intervals were?". Somebody will answer: "1 hour" and the answer would be partially correct. A more correct answer would be 1 + 24 n hours, with n = 0, 1, 2, 3�. The world of FT-NMR is similar. The difference is that the regular interval between consecutive observation is known in advance while the speed of the hands and of the shadow is unknown. In other words, it is the opposite of my example of the tower. The equivalent of a day, in the world of FT-NMR, is very very short and is...

This is a doublet of doublets. If you move one doublet towards the other, for example by increasing the smaller J, the central peaks will coalesce into a single peak of double intensity (the algebraic sum of the central peaks). A triplet is a special case of doublet of doublets (the Js are identical). Another doublet of doublets. This time the smaller coupling is anti-phase. If we increase the small J, we'll see another algebraic addition. This is a triplet. Right?

Here is where the real fun begins. I was not joking with my previous post. You can really do these things at home. The simple instructions are available on another site , and they are illustrated. After completing the tutorial (it takes 5 minutes in total) a working application will remain in your hard disc, and you will be free to apply the same treatment to your own spectra. iNMR has always been available as a free download (since 2005). Access is unlimited and the program never expires. Other specialized simulation modules are included to cover most of the needs of an advanced spectroscopist (the few exceptions are motivated by the fact that other needs were already covered by existing freeware). My blog is three years old. Half of the comments have been dedicated to a single post, which is clearly (and purposely) the least representative of the blog. When people find something useful (and this is certainly the case today) and free, they don't comment. If you are not going to co...

Returning to the DQF-COSY of taxole, I have found this challenge: I couldn't tell which kind of multiplet it was. I have extracted the section corresponding to the red line and moved it into my novel simulator. Then I have introduced 3 couplings and pushed the "Fit" button. That's all. The goodness of the fit is convincing. It is a doublet of doublets of doublets and the Js are: 14.7, 6.4 and 9.9 Hz. The latter corresponds to an antiphase coupling. Not only I know which kind of multiplet it is, I have also measured the Js! You might feel it's funny, I find it amazing, perhaps somebody will say it is useful. "The coupling constants were extracted from the DQF-COSY by the blogger's simulator".

I am continuing my explorations on board of my new multiplet simulator. It has been easy to simulate an asymmetric doublet. Here the asymmetry is only apparent and is due to the limited digitization. As explained yesterday, the black line belongs to an experimental 2-D spectrum (today I have chosen a TOCSY), the red line is a theoretical doublet acquired and processed under the same conditions. My simulator allows me to change the frequency by dragging the blue label at the bottom. In this way the coupling remains constant. It turns out that my spectrum was a middle-range case. With a slight increase of the chemical shift I can obtain a symmetric doublet, or even a singlet!