[ase-users] spacegroup question

[Lars Grabow]

Hi,

I tried to use the ase spacegroup package to make the L_10 bulk structure (http://cst-www.nrl.navy.mil/lattice/struk/l1_0.html)

I expected to get the correct results with this command:

bulk = crystal(['Cu','Au'],[(0,0,0),(0.5,0.0,0.5)], spacegroup=123, cellpar=[a,a,c,90,90,90])

However, when I build this bulk structure, one Cu atom seems to be missing.
The correct structure is obtained when I add an extra Cu atom like this:

bulk = crystal(['Cu','Cu','Au'],[(0,0,0),(0.5,0.5,0.0),(0.5,0.0,0.5)], spacegroup=123, cellpar=[a,a,c,90,90,90])

Am I using the spacegroup package correctly, or is this possibly a bug?

Thanks!
Lars

-------------------------------------------------------------------------------------------------------------
Lars C. Grabow
Assistant Professor of Chemical and Biomolecular Engineering
University of Houston
S341 Engineering Building 1
Houston, TX 77204-4004
email: grabow at uh.edu			web: http://www.chee.uh.edu/faculty/grabow
phone: (+1) 713-743-9899		fax: (+1) 713-743-4323



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