When performing high temperature/high pressure and/or phase transition experiments, it can be important to determine the unit cell results as quickly as possible so this information can be used to plan the next experiment. With Rietveld software using structureless Le Bail fitting, this becomes quite possible even on low quality patterns with impurity peaks due to the whole pattern Le Bail fitting refinement being limited to HKL lines defined by the cell and spacegroup. This can result in a very high quality unit cell refinement with overlapping impurity reflections becoming obvious. A trick here (that should work with other software such as Fullprof, Powder Cell etc) with LHPM-Rietica is to copy over the optimised HKL file to the next file in the series. This assumes you have optimised your first (and checked out the middle and end pattern of the series). For information on setting up the first file, refer to Setting up Rietica for doing Le Bail whole profile unit cell refinement In the following example, initial optimisation found that for this data (Cubic I A 3 D with a=b=c=11.82): Peak profile could be adequately fitted with V W width and the first gamma shape parameter Background was happy with a Shifted Chebyshev I with 3 released parameters. An area of the pattern was excluded (use Right Mouse Button, Insert Excluded) (the blue area in the following screen dumps) that had a nasty impurity peak and overlapped higher up in the sequence with a 0 4 4 peak. It was found other impurity peaks did not cause much of a problem with the refinement. 30 cycles was a good number to perform in this case to ensure convergence. It is useful to have as defaults (via File, Preference: automatic assign data file name, DON'T use a temporary directory, Refine at start and update boxes ticked.

copy 000%1.inp 000%2.inp 
copy 000%1.hkl 000%2.hkl

Applying HKL and input files from dataset 3 to dataset 4

Applying HKL and input files from dataset 4 to dataset 5

Applying HKL and input files from dataset 5 to dataset 6