On Wed, Jan 25, 2017 at 8:48 AM, Mihalis Kavousanakis <[email protected]> wrote: > Dear all, > > I have a question regarding ibrav=3 crystal axes, which are reported as > v1=(a/2)(1,1,1), v2=(a/2)(-1,1,1), v3=(a2/2)(-1,-1,1) > > Should these be rather: > v1=(a/2)(-1,1,1), v2=(a/2)(1-,1,1), v3=(a2/2)(1,1,-1) ?
they should, but they aren't, for reasons nobody knows any longer since many years (that part of the code likely dates back to the 70's). Unfortunately it is not possible to change it without breaking existing input data. The only thing one might do is to add a "ibrav=-3" case with a more sensible choice of axis. > I encountered this problem when I performed an scf simulation on a > Molybdenum Im-3m crystal in its primitive form. > The crystal's dimensions are a=b=c=2.725Angstrom, and > alpha=beta=gamma=109.47 deg. > > The crystal axes as reported in the output file however would give: > a=b=c=2.725Angstrom, and alpha=beta=70.53deg, beta=109.47 deg. are you explicitly using the space group and Wyckoff positions? and are you getting wrong positions? or just a funny set of alpha beta gamma angles? Paolo > I am runnning on QE 5.2.1 > > > kind regards, > Mihalis Kavousanakis > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
