# pt2

> Second order perturbative correction to the wave function contained in the EZFIO directory.

> This programs runs the stochastic PT2 correction on all “n_states” wave function stored in the EZFIO folder (see `determinant n_states`).

> The option for the PT2 correction are the “pt2_relative_error” which is the relative stochastic

> error on the PT2 to reach before stopping the stochastic sampling. (see `perturbation pt2_relative_error`)

> Needs:

> `is_zmq_slave` `mo_two_e_integrals_in_map` | `psi_energy` `threshold_generators` | `read_wf`

> Calls:

> `run()` | `run_slave_cipsi()` |

> Touches:

> `fock_matrix_ao_alpha` `fock_matrix_ao_alpha` `mo_coef` `distributed_davidson` | `level_shift` `mo_coef` `pt2_e0_denominator` `pt2_stoch_istate` | `read_wf` `state_average_weight` `threshold_generators`