A QED-Hartree-Fock (HF) calculation is performed by specifying a QED-HF (`qed-hf`

) wavefunction
in the method section of the input file. To start a ground state
QED-HF we specify

```
method
qed-hf
end method
do
ground state
end do
```

A minimal working example for a QED-HF single-point calculation on water with wavevector \(\vec{k}=(0,0,1)\), frequency \(\omega=0.5\) au and coupling \(\lambda=0.05\) au:

```
system
name: H2O
charge: 0
end system
do
ground state
end do
method
qed-hf
end method
qed
modes: 2
wavevector: {0.0, 0.0, 1.0}
frequency: {0.5, 0.5}
coupling: {0.05, 0.05}
end qed
geometry
basis: cc-pVDZ
H 0.86681 0.60144 0.00000
H -0.86681 0.60144 0.00000
O 0.00000 -0.07579 0.00000
end geometry
```

Save this as `h2o.inp`

and invoke the launch script.

```
path/to/eT_launch.py h2o.inp
```

After the calculation finished you should find `h2o.out`

and `h2o.timing.out`

in your working directory. If the calculation exited successfully
(look for `eT terminated successfully!`

at the bottom of the file),
a summary of the calculation should be printed at the end.