# G0W0 calculations#

## Setting up the first G0W0 calculation#

Once completed the preliminary steps, we are ready to run a G0W0 calculation

for simplicity in the common Godby-Needs plasmon-pole approximation (PPA). In particular we compute the direct band gap at Gamma of hBN. The core of the inputs are the parameters, which will be written in the input file that is used to feed the yambo executable. We follow the aiida-yambo/examples/plugin/yambo_gw.py example.

The quasiparticle corrections and the renormalization factors can be accessed from the Yambo calculation (yambo_calc) using the output bands and array data:

```
yambo_calc = load_node(pk)
energies_DFT = yambo_calc.outputs.array_ndb.get_array('E_0')
QP_corrections = yambo_calc.outputs.array_ndb.get_array('E_minus_Eo')
Z_factors = yambo_calc.outputs.array_ndb.get_array('Z')
kpoint_band_array = yambo_calc.outputs.array_ndb.get_array('qp_table')
kpoints = yambo_calc.outputs.bands_quasiparticle.get_kpoints()
```

To retrieve additional files, you can provide their names in the input settings Dict:

```
settings = Dict(dict={"ADDITIONAL_RETRIEVE_LIST":['r-*','o-*','LOG/l-*01',
'aiida.out/ndb.QP','aiida.out/ndb.HF_and_locXC']})
builder.use_settings(settings)
```

This selects the additional files that will be retrieved and parsed after a calculation. Supported
files include the report files `r-*`

, text outputs `o-*`

, logs, the quasiparticle
database for GW calculations `aiida.out/ndb.QP`

, and the Hartree-Fock and local exchange
db `aiida.out/ndb.HF_and_locXC`

. Actually, all the files above are automatically collected from the plugin: quantities
that you may want collect to further analyse are for example the dipoles or the dielectric function databases, output of a typical GW
calculation.

It is possible also to run Bethe-Salpeter equation calculations - to compute optical properties - as shown in the next sections of this tutorial.

If you want to run a single G0W0/BSE simulation within the aiida-yambo plugin, we suggest to always use the YamboWorkflow workchain provided in the plugin and shown in the following sections.