Dear Aldino, Welcome to the relax mailing lists. You can for sure use relax to analyse single field strength data, but it is not recommended. relax will do everything Modelfree4 and Dasha will do, plus a lot more. This is not reachable from the GUI though, you will have to implement this in a special script. There are some sample scripts which partly implement this (see the sample_scripts directory), but to put together a full analysis, you will have to do some serious scripting. You have to do this anyway with Modelfree4 or Dasha, as you have to iteratively optimise the diffusion tensor and model-free parameters until convergence (see my paper d'Auvergne and Gooley, 2007 (http://dx.doi.org/10.1039/b702202f) for a review of this procedure, and d'Auvergne and Gooley, 2008b (http://dx.doi.org/10.1007/s10858-007-9213-3) for recent advances). Note that there are many, many issues with using only single field strength data. These are explained in full detail in my review (d'Auvergne and Gooley, 2007). The major problem is that the axial symmetry and rhombicity of the diffusion tensor can be mixed up with chemical exchange and large amplitude ns motions. With single field strength data, the difference between the global diffusion and internal motions can often not be distinguished resulting in either artificial internal Rex and/or ns motions, or the diffusion tensor is incorrect hiding the internal motions of the molecule. Only with multiple field strength data can you distinguish the differences. You sometimes also need to apply the new methodology in d'Auvergne and Gooley, 2008b. This is why you will almost never see a publication with only single field strength data today. Note that using single field strength data, you have to revert to using the state of the art from 1995 (see the Mandel, Akke, and Palmer 1995 paper). Your analysis will be almost two decades behind the current state of the art (some of this is in the links at http://www.nmr-relax.com/refs.html). I hope this information helps. Regards, Edward P. S. This has been asked a number of times before. See https://mail.gna.org/public/relax-users/2008-03/msg00004.html and the links and threads therein for the past discussions. On 20 September 2011 16:23, Aldino <aldinoviegas@xxxxxxxxxxxxx> wrote:
Dear all, I am using the most recent version of Relax to try to calculate some dynamic parameters... The thing is that I only have data at one frequency (600 MHz) and when I try to run the model-free calculation it sais that it need 4 or more data sets... How can I calculate the model-free parameters with only 3 data sets (NOE, R1 and R2)? Thank you in advance, Aldino Viegas ______________________________________________ Aldino Viegas, PhD Student Dep. Química, REQUIMTE Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa 2829-516 Caparica, Portugal Tlf. +351 212948300 Ext. 10900 Lab. 106-A aldinoviegas@xxxxxxxxxxxxx _______________________________________________ relax (http://nmr-relax.com) This is the relax-users mailing list relax-users@xxxxxxx To unsubscribe from this list, get a password reminder, or change your subscription options, visit the list information page at https://mail.gna.org/listinfo/relax-users