Re: [Pw_forum] XCRYSDEN Primitive cell: Reg
On Tue, 2016-01-19 at 13:48 +0530, Suresh A wrote: > Dear All, > Herewith I have included two primitive cell input filefor anatase > strucutre. Between them XCRYSDEN shows correct structure for file one where > atomic positions are in angstrom unit and for another structure it shows > wrong strucutre where atomic positions are in relative crystal coordinate. > Will you please point out where the problem is? And I am using > xcrysden-1.5.60-semishared linux Typically such problems stem from the following reason: the user and the program have a different idea of the unit-cell. In particular, there are two flavors of these problems: (i) the crystallographic vectors are chosen differently between the user and the program (in such cases specified Cartesian coordinates do not give correct structure) (ii) the crystallographic coordinates refers to different set of vectors, e.g, primitive vs. conventional (in such cases the specified crystal coordinates do not give the correct structure) In your case it is the second problem. You have specified the crystal coordinates with respect to conventional vectors, but the pw.x expects the coordinates wrt primitive vectors (and consequently also xcrysden interprets the QE input this way). -- Excerpt from the pw.x documentation: -- crystal : atomic positions are in crystal coordinates, i.e. in relative coordinates of the primitive lattice vectors as defined either in card CELL_PARAMETERS or via the ibrav + celldm / a,b,c... variables Best regards, Tone -- Anton Kokalj J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel: +386-1-477-3523 // fax:+386-1-477-3822) Please, if possible, avoid sending me Word or PowerPoint attachments. See: http://www.gnu.org/philosophy/no-word-attachments.html ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
[Pw_forum] XCRYSDEN Primitive cell: Reg
Dear All, Herewith I have included two primitive cell input file for anatase strucutre. Between them XCRYSDEN shows correct structure for file one where atomic positions are in angstrom unit and for another structure it shows wrong strucutre where atomic positions are in relative crystal coordinate. Will you please point out where the problem is? And I am using xcrysden-1.5.60-semishared linux version. input file1: &CONTROL title = 'TiO2' , calculation = 'scf', outdir ='$TMP_DIR/' prefix = 'anatase', pseudo_dir = '$PSEUDO_DIR/', / &SYSTEM ibrav = 7, celldm(1) = 7.1356, celldm(3) = 2.51218, nat = 6 , ntyp = 2 , ecutwfc = 30.00 , ecutrho = 300, / &ELECTRONS conv_thr = 1.0d-09, / ATOMIC_SPECIES O 15.999 O.pw91-van_ak.UPF Ti 47.867 Ti.pw91-nsp-van.UPF ATOMIC_POSITIONS angstrom Ti 0.0 0.0 0.0 Ti 0.0 1.88800 2.37150 O0.0 0.0 -1.983097630 O0.0 0.0 1.983097630 O0.0 1.88800 0.387796645 O0.0 1.88800 4.355203355 K_POINTS automatic 4 4 4 0 0 0 INPUTFILE 2 &CONTROL title = 'anatase' , calculation = 'scf' , restart_mode = 'from_scratch' , pseudo_dir = '/home/suresh/GN2/', outdir ='/home/suresh/Desktop/primitivecell/tmp/', prefix = 'anatase' , tstress = .true. , tprnfor = .true. , / &SYSTEM ibrav = 7, celldm(1) = 7.153, celldm(3) = 2.513, nat = 6, ntyp = 2, ecutwfc = 60 , exxdiv_treatment = 'none' , / &ELECTRONS / &IONS / &CELL / ATOMIC_SPECIES Ti 47.86700 Ti.pz-mt_fhi.UPF O 15.99940 O.pz-mt_fhi.UPF ATOMIC_POSITIONS (crystal) Ti 0.000 0.000 0.000 Ti 0.000 0.500 0.250 O 0.000 0.000 0.208 O 0.000 0.000 -0.208000 O 0.000 0.500 0.458 O 0.000 0.500 -0.042000 K_POINTS automatic 4 4 2 1 1 1 With Regards, A.Suresh, Research Scholar, Madurai Kamaraj University, Madurai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
