Dear all I'm refining some tof neutron data from a single crystal using Fullprof. In the data there are also two columns with the calculated absorption correction and t bar. I obtained a good refinement but the refined values of the extinction parameters are quite big and some are negative:
! Extinction Parameters ! Ext1 Ext2 Ext3 Ext4 Ext5 Ext6 Ext7 Ext-Model 72.45 72.58 91.81 104.0 -70.52 -26.96 0.000 4 I'm not expert of extinction parameters: are the obtained values feasible? If I fix to zero the extinction parmeters 4, 5 and 6, the new values of the refined extinction parameters are much smaller ! Ext1 Ext2 Ext3 Ext4 Ext5 Ext6 Ext7 Ext-Model 15.03 16.29 55.20 0.000 0.000 0.000 0.000 4 but also the thermal factors become much smaller and one is negative. The chi value doesn't change pratically in the two refinements. What do you reckon about it? Which fit is more correct? It seems to me there is a strong correlation among extinction parameters, thermal factors and scale factor. Many thanks for your advices with regards Stefano Agrestini ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
