Dear Artur
your system contains one atom per unit-cell, if you want to describe the same system using a super-cell which containing 8 atoms. You have to: - double your lattice constant celldm(1) from 7.5 to 15; - set to 8 the number of atoms (nat) - set to 2 the number of types (ntyp) - set the 8 atomic positions ( cartesian coordinates using alat units ) to Al 0 0 0 Al 0.5 0 0 Al 0. 0.5 0.0 Al 0.0 0.0 0.5 Al 0.5 0.5 0.0 Al 0.5 0.0 0. 5 Al 0.0 0.5 0.0 Al 0.5 0.5 0.5 and then you can change any of the 8 Al to Si and you are done regards Pietro On 13/11/2016 16:56, [email protected] wrote: > Dear All, > > I have a simple cubic structure (8 atoms at corners), for example: > > &system > ibrav= 0, celldm(1) =7.50, nat= 1, ntyp= 1 > / > CELL_PARAMETERS {alat} > 1.000000000000000 0.000000000000000 0.000000000000000 > 0.000000000000000 1.000000000000000 0.000000000000000 > 0.000000000000000 0.000000000000000 1.000000000000000 > ATOMIC_SPECIES > Al 26.98 Al.pz-vbc.UPF > ATOMIC_POSITIONS > Al 0.00 0.00 0.00 > > Is it possible to change only one atom in this system, for example I would > like to replace Al by Si at one corner and leave remaining 7 corners > occupied by Al? > > Best Regards, > Artur _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
