davewragg
Dear All,
I'm looking at clusters inside framework materials. The clusters have quite low occupancy and their atoms sit on special positions (most of the framework atoms are on general positions). If I want to extrapolate back from the crystal structure to the local environment at a single cluster, do I need to correct the occupancies for the site multiplicities? I ask because doing so seems to give more reasonable answers, but I'm not sure if it is really correct and I couldn't find anything in the tech reference which indicated how such things are treated in the TOPAS algorithms.
Thanks,
Dave
rowlesmr
Hi Dave
Occupancies go from 0 -- 1 and the value is independent of multiplicity.
If you have an occupancy of 1 on a 48e site, you have 48 atoms in the unit cell. If it is 0.75 on a 96j site, then you have 72 atoms in the unit cell.
See S10.19 "Occupancies and symmetry operators" in tech ref.
Matthew