Cd Si volume relaxation: Difference between revisions

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**Alternatively we relax the structure with VASP "on the fly" ({{TAG|IBRION}}=2 and {{TAG|ISIF}}=3)
**Alternatively we relax the structure with VASP "on the fly" ({{TAG|IBRION}}=2 and {{TAG|ISIF}}=3)


*From equation of states we determine lattice parameter of <math>a=5.4687 \AA</math> (volume scan plus Murnaghan EOS using {{TAG|ENMAX}}=400).
*From equation of states we determine lattice parameter of <math>a=5.4687</math> <math>\AA</math> (volume scan plus Murnaghan EOS using {{TAG|ENMAX}}=400).





Revision as of 18:56, 8 May 2017

Task

Relaxation of the internal coordinates, volume and cell shape in cd Si.

Input

POSCAR

cubic diamond
   5.5
 0.0    0.5     0.5
 0.5    0.0     0.5
 0.5    0.5     0.0
  2
Direct
 -0.125 -0.125 -0.125
  0.125  0.125  0.125

INCAR

System = diamond Si
ISMEAR = 0; SIGMA = 0.1;
ENMAX  =  240
IBRION = 2; ISIF=3 ; NSW=15
EDIFF  = 0.1E-04
EDIFFG = -0.01
  • IBRION=2 conjugate-gradient algorithm.
  • ISIF=3 change of internal parameter, shape and volume simultaneously.

KPOINTS

k-points
 0
Monkhorst Pack
 11 11 11
 0  0  0

Calculation

  • To determine the equilibrium volume we can:
    • Fit the energz over a certain volume range to an equation of state (see cd_Si.
    • Alternatively we relax the structure with VASP "on the fly" (IBRION=2 and ISIF=3)
  • From equation of states we determine lattice parameter of (volume scan plus Murnaghan EOS using ENMAX=400).


Download

diamondSivolrel.tgz


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