Cavity Born-Oppenheimer calculation

If you have not already done so, you should take a look at the eT_launch page to get an understanding of how the launch script works.

Setting up a CBO calculation

A Cavity Born-Oppenheimer ground state calculation can be performed with a HF, CC or CI wave function. The photonic degrees of freedom are treated as a non-polarizable embedding. To perform a CBO calculation it is necessary to include all the sections for the corresponding HF, CC or CI calculation. Moreover, it is necessary to include the boson specifying for every mode of the field the displacement coordinate q with the keyword cbo .

A minimal working example for a Hartree-Fock calculation in Cavity Born-Oppenheimer approximation is:

- do
  ground state

- method

- boson
  cbo:         {0.1}
  interaction type: photon
  modes:        1
  frequency:    {0.5}
  wavevector:   {0, 0, 1}
  coupling:     {0.05}

- geometry
  basis: cc-pVDZ
  H          0.023452    0.185621    0.000000
  H          0.906315    1.422088    0.000000
  O          0.009319    1.133156    0.000000

At the end of the output file you can find the computed energy.

Relevant input sections

Solver SCF

Solver coupled cluster ground state