Hi all, I read the discussion on negative Debye waller factor. As per the discussion the negative value of this factor shows that the model has shortcomings, so it should be corrected. I am also getting the same problem while fitting one of my samples. It is a Cu complex whose EXAFS data is taken at Dispersive EXAFS beamline at RRCAT, Indore, India. In the complex the nearest neighbours of Copper atom are Nitrogen and Oxygen. I am getting a very good fit upto 3rd shell but the problem is that all ss parameters are coming negative. I checked the model it seem correct. Also I am getting a peak below 1 Angs which is also getting fitted but I am not able to get that whether it is a real or due to some noise. I am attaching herewith the results of data analysis and fitting. Thanks in advance With regards Abhijeet Gaur Vikram University Ujjain, INDIA