[Ifeffit] TkAtoms weirdness

[Peter Pfalzer]

Hi all,

I encountered a problem similar to the one Carlo describes in his mail.
I believe there is a bug in how TkAtoms reads 90 deg. angles from input 
files and (maybe) treats trigonal systems in hexagonal notation.

Carlo: After reading in the input file, complete the lattice parametes 
by hand, i.e. enter the angles (90 deg) into the blank fields for alpha 
and beta. Then the calculation should work.

If you don't enter the angles manually TkAtoms will obscure your 
structure. Watch the lattice parameters *after* running atoms! The value 
for the c axis will have changed so that a=b=c and you will get 
alpha=beta=gamma=120 deg.

The other day I complained to Bruce about the calculation of the unit 
edge length (in the absorption card), printing out way to large sample 
thicknesses for an edge step of 1.
In the meantime I noticed that the values for absorption length and unit 
edge length depend on whether I use the trigonal or the rhomohedral 
representation for my unit cell.
Bruce: The values for the trigonal unit cell seem okay, maybe the 
problem is the treatment of the rhombohedral structure (not the specific 
wheight as I originally speculated). I have attached the two input files.

Hope I could help!

Best,
Peter


-- 
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Peter Pfalzer
Universitaet Augsburg                    Tel: +49-821-598-3215
Lehrstuhl fuer Experimentalphysik II     Fax: +49-821-598-3411
Universitaetsstr. 1
D-86135 Augsburg
Germany                   Peter.Pfalzer at physik.uni-augsburg.de
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