Equilibrium volume of Si in the RPA

Task

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

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

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.