kunyang
I did some refinement for TOF data about Al2O3 and Al2O3/Al2TiO5 bulk samples. I made "do error" to get error. With good fitting, I found that in all my refinements, the error of lattice parameter a of Al2O3 phase always be zero. Only a(Al2O3) has this problem. I post an example here: Hexagonal(@ 4.75923`_0.00000, @ 12.99278`_0.00001).
It's impossible the error be 0. I also tried to set different original lattice parameter for refine, the error here still showed zero. I think there may be some problem for my refinement.(but the fitting is really good)
Hope someone give me suggestion.
mfisch
Topas does only output five decimals. Thus, your error is just lower than 0.00000. You can create a new parameter which is equal to a_corundum/1000. This will give you three more significant decimals.