Hi,<br>thanks for the help.<br>Let me be more clear. I am trying to know the limits to use information from the second shell, from XRD I found that the phase is present,  but I want to know if I can use the signal to obtain more information about second neighbors.<br>
I have this sample and some more where I find a second shell signal, the doubt is about how far can I trust in this information, is there a limit in k-space to believe in the information of the second shell and try to fit it?<br>
I attach the R-space graph with the same limits for the FT, there are still differences, what should I check to be sure the information I can get from the second shell is trustable and not a problem of the noisy signal?<br>
Thanks, euG<br><br>