Talk:Relaxation (NMR)
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I have a serious problem with this page. NMR relaxation is a very broad phenomena (and very complicated), which has very different characteristics depending on the exact physical conditions where it occurs. I feel this page consideres only one specific case. For instance T2 (in contrast to T1) is much MORE dependant on the magnetic field in solution NMR on large molecules and in the case of small molecules they are nearely the same. NMR relaxation is an important issue in all applications of NMR (not just MRI). I think this page gives a very misleading picture of NMR relaxation, without explainig what NMR relaxation is. I would like to correct this page but, I know very little about NMR relaxation in the solid state or about the use of the concept in MR Imaging, so I would be gratefull for some feedback. -- Flogiston
- You forgot to sign your name. :) I am currently a student with a major in MRI, and still know very little about the whole picture of it, not to mention NMR in a standard chemistry sense. What I put on is to summarize some info about the relaxation I've learned these 2 plus years, since there were no more detailed info about this in Wikipedia as far as I knew. This page is not complete in my opinion. You can still make this page better by sharing your knowledge about it. --KasugaHuang 06:55, 5 December 2006 (UTC)
As someone who has spent a lot of his life doing NMR I can only agree that this article needs a lot of expansion. Unfortunately I don't have the time to do it. Topics that should be added would be Relaxation Mechanisms, Relaxation in organic vs inorganic systems, Molecular motions and their relationship to relaxation, Measurement of T1 and T2, Quadrupolar effects, Anisotropic media and many others. nmrtian
There should also be a section on T1 rho, spin-lattice relaxation in the rotating frame. -- jpdemers
is it just me or should the longitudinal relaxation refer to the component of M that is pointing PARALLEL to B0 instead of perpendicular? -dc
[edit] Comment
This was posted in the middle of the introductory section by 86.140.114.210:
it depends what kind of relaxation we have (if we observe orientation related proceses, then this explanation is correct, if not then it is not correct). In fact, most of spectroscopic technics are based on absorbtion of EM energy by matter (in most cases electron), and in this sense we have no orientation efects, but only changes in number of resonating particles. A fully relaxed state or equilibrium means that all free for that system absorbtion sites are able to bring their own contribution to the resonanse. The opposite notion is saturation, that means no more active (at that time moment) absorbtion sites. Resonance means that at the same time moment (or some very short time which does not affect significantly the spectrum, it has constant contribution) we have absorbtion in volume. This short time interval and sample volume (more precisely the thickness) contribute in the line broadening and are neglected in analysis. In fact, spins are oriented by the external magnetic field in order to obtain the resonance (in other words to get the organised simultaneous absorption). The described above event could take place only then after reaching equilibrium with the applied magnetic field, we sudenly switch it off and look in the temperature dependent spin depolarisation effect. In the sence of magnetic resonance, the relaxation simply means how fast reacting centers release the absorbed EM radiation (and it means that they are able to participate in the resonance again).
It isn't encyclopedic, which is why I moved it here, but I have no idea how correct or otherwise it is. Sectori (talk) 11:52, 8 January 2008 (UTC)
Here's a question for someone who knows this topic well. On the page, where it says: "Different physical processes are responsible for the relaxation of the components of the nuclear spin magnetization vector M parallel perpendicular to the external magnetic field," which is it, parallel or perpendicular? --Tekhnofiend (talk) 06:39, 5 March 2008 (UTC)
