Equilibrium volume of Si in the RPA: Difference between revisions

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=== Step 1 ===
=== Step 1 ===


*DFT groundstate calculation with a “dense” mesh of k-points
*The following {{TAG|INCAR}} file is used (INCAR.DFT):
{{TAGBL|ISMEAR}} = 0 ; {{TAGBL|SIGMA}} = 0.05
{{TAGBL|EDIFF}} = 1E-8
*The following {{TAG|POSCAR}} file is used (KPOINTS.12):
12x12x12
  0
G
  12 12 12
  0  0  0
----
----
== Used INCAR Tags ==
== Used INCAR Tags ==

Revision as of 09:49, 3 April 2018

Task

Calculation of the equilibrium lattice constant of Si in the RPA (ACFDT).

Input

POSCAR

system Si
  5.8
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00
0.25 0.25 0.25

Calculation

The workflow of RPA total energy calculations consists of five consecutive steps:

  • Step 1: a “standard” DFT groundstate calculation with a “dense” mesh of k-points.
  • Step 2: compute the Hartree-Fock energy using the orbitals of Step 1. Needs WAVECAR file from step 1.
  • Step 3: a “standard” DFT groundstate calculation with “coarse” mesh of k-points.
  • Step 4: obtain DFT “virtual” orbitals (empty states). Needs WAVECAR file from step 3.
  • Step 5: the RPA correlation energy (ACFDT) calculation. Needs WAVECAR and WAVEDER files from step 4.

In case of metallic systems there is an additional step between Steps 4 and 5, that is beyond the scope of this example.

All of the calculation steps are prepared in the script doall.sh.

Step 1

  • DFT groundstate calculation with a “dense” mesh of k-points
  • The following INCAR file is used (INCAR.DFT):
ISMEAR = 0 ; SIGMA = 0.05
EDIFF = 1E-8
  • The following POSCAR file is used (KPOINTS.12):
12x12x12
 0
G
 12 12 12
  0  0  0

Used INCAR Tags

AEXX, AGGAC, ALDAC, ALGO, EDIFF, ISMEAR, KPAR, LHFCALC, LOPTICS, LWAVE, NBANDS, NELM, NKRED, NOMEGA, SIGMA, SYSTEM

Download

Si_ACFDT_vol.tgz

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