O atom spinpolarized low symmetry: Difference between revisions
Vaspmaster (talk | contribs) |
|||
| (24 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
{{Template:At_and_mol - Tutorial}} | |||
== Task == | |||
Performing a spin-polarized low symmetry calculation of a single oxygen atom in a non cubic box to get the right energy minimum. | |||
== Input == | |||
=== {{FILE|POSCAR}} === | |||
O atom in a box | O atom in a box | ||
1.0 ! universal scaling parameters | 1.0 ! universal scaling parameters | ||
| Line 20: | Line 16: | ||
cart ! positions in cartesian coordinates | cart ! positions in cartesian coordinates | ||
0 0 0 | 0 0 0 | ||
=== {{FILE|INCAR}} === | |||
{{TAGBL|SYSTEM}} = O atom in a box | |||
{{TAGBL|ISMEAR}} = 0 ! Gaussian smearing | |||
{{TAGBL|SIGMA}} = 0.01 | |||
{{TAGBL|ISPIN}} = 2 ! spin polarized calculation | |||
=== {{FILE|KPOINTS}} === | |||
Gamma-point only | |||
0 | |||
Monkhorst Pack | |||
1 1 1 | |||
0 0 0 | |||
== Calculation == | |||
*In the GGA most atoms are characterized by a symmetry broken solution. VASP, however, symmetrizes the charge density according to the determined symmetry of the cell. Check the {{TAG|OUTCAR}} file, to see what symmetry VASP is using. | |||
*To lower the symmetry, simply change the lattice parameters to 7.0, 7.5 and 8.0 in the {{TAG|POSCAR}} file (see the example file above) and reduce {{TAG|SIGMA}} to {{TAG|SIGMA}}=0.01 in the {{TAG|INCAR}} file. | |||
*By rerunning VASP one finds a much lower energy: | |||
vasp.5.4.1 05Feb16 (build Aug 22 2016 16:46:23) complex | |||
... ... . .. | |||
DAV: 15 -0.189071145737E+01 -0.29321E-03 -0.39183E-05 48 0.478E-02 0.995E-03 | |||
DAV: 16 -0.189071145737E+01 -0.27775E-03 -0.39294E-05 40 0.290E-02 0.541E-03 | |||
DAV: 17 -0.189104076616E+01 -0.51555E-04 -0.34087E-06 48 0.132E-02 | |||
1 F= -.18910408E+01 E0= -.18910408E+01 d E =-.309633E-20 mag= 1.9998 | |||
== Further things to try == | |||
*How does the energy change when one decreases {{TAG|SIGMA}} to {{TAG|SIGMA}}=0.01 in the {{TAG|INCAR}} file? Why? | |||
== Download == | == Download == | ||
[ | [[Media:Oatomspinlowsym.tgz|Oatomspinlowsym.tgz]] | ||
{{Template:At_and_mol}} | |||
[[Category:Examples]] | [[Category:Examples]] | ||
Latest revision as of 14:16, 14 November 2019
Overview > O atom > O atom spinpolarized > O atom spinpolarized low symmetry > O dimer > CO > CO vibration > CO partial DOS > H2O >
H2O vibration > H2O molecular dynamics > Further things to try > List of tutorials
Task
Performing a spin-polarized low symmetry calculation of a single oxygen atom in a non cubic box to get the right energy minimum.
Input
POSCAR
O atom in a box 1.0 ! universal scaling parameters 7.0 0.0 0.0 ! lattice vector a(1) 0.0 7.5 0.0 ! lattice vector a(2) 0.0 0.0 8.0 ! lattice vector a(3) 1 ! number of atoms cart ! positions in cartesian coordinates 0 0 0
INCAR
SYSTEM = O atom in a box ISMEAR = 0 ! Gaussian smearing SIGMA = 0.01 ISPIN = 2 ! spin polarized calculation
KPOINTS
Gamma-point only 0 Monkhorst Pack 1 1 1 0 0 0
Calculation
- In the GGA most atoms are characterized by a symmetry broken solution. VASP, however, symmetrizes the charge density according to the determined symmetry of the cell. Check the OUTCAR file, to see what symmetry VASP is using.
- To lower the symmetry, simply change the lattice parameters to 7.0, 7.5 and 8.0 in the POSCAR file (see the example file above) and reduce SIGMA to SIGMA=0.01 in the INCAR file.
- By rerunning VASP one finds a much lower energy:
vasp.5.4.1 05Feb16 (build Aug 22 2016 16:46:23) complex ... ... . .. DAV: 15 -0.189071145737E+01 -0.29321E-03 -0.39183E-05 48 0.478E-02 0.995E-03 DAV: 16 -0.189071145737E+01 -0.27775E-03 -0.39294E-05 40 0.290E-02 0.541E-03 DAV: 17 -0.189104076616E+01 -0.51555E-04 -0.34087E-06 48 0.132E-02 1 F= -.18910408E+01 E0= -.18910408E+01 d E =-.309633E-20 mag= 1.9998