Summary:
Try and setup a file, then email it over
with the official starting structure - and some data.
(You must know the geometry and accurate slit settings
of your lab diffractometer for FP to work well).
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I find it difficult to do a general summary ofhow to run Koalariet in one line answer, though I should warn that fans ofASCII input/control files may be offended by someof the following:
90% of initial pain is setting up the input file.Main trick then is on how to set refinement flags anduse the equations facility. I must admit never having consulted what documentation exists - asmost of this was done through habit and asking otherusers. The example files are sort of the documentation.(Not sure if this is all that uncommon with developmental Rietveld software?)
Quick method to start off:You should be able to take an example file like y2o3.inpand just substitute your values in.
Be wary for special positions - it requires the accurate value - 1/3 is not the same as 0.333333You would use the fraction to describe thespecial position as 0.333333 would be considereda general position. Also, ICSD "standard" settingsare used for the space groups.
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Few more points:
It only works on Win 95.
All files have to be on the C: hard-disk
Hopefully without causing too much offence - I would consider this a developmental/example Rietveld in terms ofthe algorithmic approach it uses. It lacksanisotropic thermals, cannot do neutrons, cannot properlyhandle synchrotron data, does not give an R Bragg oran output file you can do a Fourier Fobs or Fdif on.Also, it does not give a difference plot down the bottom of the XFIT screen which is a real bummer.
Not having the option of a GUI could give a superficial impression this is a program that is still living in the 70's(?) - despite being written from scratch in C in the 1990's. FP algorithms are definitely modern and I would guess this also takes advantage of the leapsand bounds new algorithms which has occured since the days ofthe 1960s and computers with X Kb of memoery (where X is a rather small number).
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Despite the above:
On lab XRD data - it can do fabulous stuffin terms of stability and fitting, plus linking ofparameters. It also has MIN and MAX macros so forthings like UNIT-CELL in multi-phase data - you cankeep it within reasonable values when starting offthe refinement. Same with the scale factors - MIN = 0.00000000001; stops it going negative.
Again describing this all generally could take up a bit of space. Email box has already grown since starting the reply
Lachlan.
PS: Would like to get around to putting a few tutorials onKoalariet together - but have around a dozen or so higher onthe list for the CCP14 tutorial page.
> I am interested in perform Rietveld refinements with Koalariet. > We have downloaded the program from the CCP14 suite, and we have found> excellent information > for the auxiliary program Xfit, but the instructions to build the input > file *.inp are very confusing and uncomplete.> Can someone help me!?> Best regards from> Paco Luis, and seven more ....>
-- Lachlan M. D. CranswickCollaborative Computational Project No 14 (CCP14) for Single Crystal and Powder DiffractionDaresbury Laboratory, Warrington, WA4 4AD U.KTel: +44-1925-603703 Fax: +44-1925-603124 E-mail: l.cranswick@dl.ac.uk Ext: 3703 Room C14CCP14 Webpage (Under heavy reconstruction): http://www.dl.ac.uk/CCP/CCP14/