Dear Paolo, I did exactly the same thing, but I expect to see all the angles to be 90, while Xcrysden does not exhibit this. How come V1 and V2 are not orthogonal? And do I have to express the fractional atomic position in terms of A,B,C or V1, V2 and V3? Amin
On Mon, Nov 28, 2011 at 3:38 AM, Paolo Giannozzi <giannozz at democritos.it>wrote: > > On Nov 28, 2011, at 6:12 , Amin Torabi wrote: > > > I have some problem in introducing a base-centered orthorhombic > > structure (ibrav=9) to QE. > > > > I have entered the cell parameters in A, B, C, cosAB, cosBC, cosAC > > you need only A, B, C (in Angstrom); cosAB, cosBC, cosAB are ignored. > Or: celldm(1)=a (in Bohr), celldm(2)=b/a, celldm(3)=c/a (celldm(4:6) > ignored). > > This is what you will get for the three unit translations v1, v2, v3 > 9 Orthorhombic base-centered(bco) celldm(2) > =b/a > celldm(3) > =c/a > v1 = (a/2, b/2,0), v2 = (-a/2,b/2,0), v3 = > (0,0,c) > > In the development version of QE, also ibrav=-9 is present: > -9 as 9, alternate description > v1 = (a/2,-b/2,0), v2 = (a/2,-b/2,0), v3 = > (0,0,c) > > P. > --- > Paolo Giannozzi, Dept of Chemistry&Physics&Environment, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Amin Torabi Ph.D. Student Chemistry Department The University *of* Western Ontario London, On Canada, N6A 5B7 Phone: 519-661-2111 Ext: 87871 **************************************** -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20111128/ac180fb1/attachment.htm
