Hartree Fock

The exchange part contribution of the self-energy for a generic state (nk) in reciprocal space reads:

It is important to note that in this way we are adding the HF contribution in a perturbative way to previously calculated DFT energies:

and hence they will differ from a standard self-consistent HF calculation.

Let's start by building up the input file for an HF calculation by typing:

$ yambo -x -V all -F hf.in

Looking inside the input file you will find:

EXXRLvcs = 1491        RL    # [XX] Exchange RL components
%QPkrange                    # [GW] QP generalized Kpoint/Band indices
  1| 14|  1|100|
%

The variable EXXRLvcs governs the number of G vector to be summed in the expression of the exchange self-energy reported above. The QPkrange name list it is a generalized index needed to select the first and last kpoints and bands we want to calculate the QP correction. Let's start by editing the hf.in file by considering the last occupied and first empty bands and check convergence of the G vectors in the summation in the Σx expression. So let's edit change the QPkrange variable in:

%QPkrange                    # [GW] QP generalized Kpoint/Band indices
   1| 14|  8| 9|
%

and

EXXRLvcs= 10 Ry

and run yambo:

$ yambo -F hf.in -J D3

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