# Neutron Structures

What goes wrong with neutron Structures

# FMAP -2 not working

In ShelXL, the FMAP -2 instruction will result in +ve and -ve peaks after refinement. This doesn’t work in olex2.refine, and the instruction will be automatically changed to FMAP 2.

# NEUT instruction not understood

olex2.refine does not seem to understand the NEUT instruction. For ShelXL, the presence of this instruction will make it use the neutron SFAC information. For olex2.refine, it is necessary to include the SFAC lines explicitly with GenDisp -n. Not a big deal, but the refinement will behave differently in the two refinement programs when only NEUT is present. Once the neutron SFAC’s are present, the refinement will proceed similarly (if not identically) in the two programs.

# EXTI in neutron refinements

The two values of a refined EXTI are very different when comparing olex.refine and ShelXL.

# Weighting Scheme and GooF for neutron refinement

The weighting schemes (and GooF values) are very different when comparing olex.refine and ShelXL