Dear Vinicius, it is not clear to me if you want to build the primitive cell of Pt3Sn or a supercell. In the former case you may use a cubic cell (ibrav=1) and put a Sn in the origin and three Pt on the faces of the cube. If you want a supercell, well, it depends if you want to extend the structure along one direction only (hence you should use a tetragonal cell) or isotropically along the three directions (the supercell will still be cubic). I don't see any reason to use ibrav=0 to specify a tetragonal cell as you are doing in your input file. Moreover it is easy to see from your input that atoms 2 and 5 will overlap with the atom in the origin (and with each other) since their positions differ by a vector of Bravais lattice.
It would be very kind of you if you take a few time to sign your future posts and specify your affiliation. Thanks! Regards, GS Il giorno 10/ago/2010, alle ore 22.06, Vin?cius Bertuzzo Lima ha scritto: > Greetings! > Before anything, thank you! > > I'm trying to optimize a super-cell of Pt-Sn intermetallic, but when I > determine the atomic positions of the crystal, there is overlapping of atoms, > which determine the species as the source. > > For example, if I determine how the platinum atom (0,0,0), the whole basis of > the crystal will, in its vertices of platinum atoms, as my only two > intermetallic is Pt3Sn > vertices of the base would be two platinum and tin. > > I understand the system, which would by ibrav = 0, but still is not working. > How would an input on which to determine the position of only two atoms of > the base and not the whole basis? > > Down my input: > > &CONTROL > calculation = 'vc-relax' , > restart_mode = 'from_scratch' , > outdir = '/home/vinicius/tmp' , > pseudo_dir = '/home/vinicius/espresso-4.1.3/pseudo' , > / > &SYSTEM > ibrav = 0, > celldm(1) = 7.10082033, > nat = 5, > ntyp = 2, > ecutwfc = 30 , > ecutrho = 300 , > occupations = 'smearing' , > degauss = 0.05 , > smearing = 'methfessel-paxton' , > / > &ELECTRONS > conv_thr = 1.D-8 , > mixing_beta = 0.7D0 , > / > &IONS > ion_dynamics = 'bfgs' , > bfgs_ndim = 3 , > / > &CELL > cell_dynamics = 'bfgs' , > cell_dofree = 'xyz' , > / > CELL_PARAMETERS cubic > 0.000000000 0.000000000 4.200000000 > 0.000000000 1.000000000 0.000000000 > 1.000000000 0.000000000 0.000000000 > ATOMIC_SPECIES > Pt 195.08400 Pt.pw91-n-van.UPF > Sn 118.71070 Sn.pw91-n-van.UPF > ATOMIC_POSITIONS alat > Pt 0.000000000 0.000000000 0.000000000 0 0 0 > Sn 1.000000000 0.000000000 0.000000000 0 0 0 > Pt 0.500000000 0.500000000 0.707100000 0 0 0 > Pt 0.500000000 0.500000000 -0.707100000 0 0 0 > Sn 0.000000000 1.000000000 0.000000000 > K_POINTS automatic > 4 4 1 0 0 0 > > Thanks again. And have a great day! > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum ? Gabriele Sclauzero, EPFL SB ITP CSEA PH H2 462, Station 3, CH-1015 Lausanne -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100811/48c49391/attachment.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 1753 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20100811/48c49391/attachment.bin
