# fcidump

`psi4.driver.``fcidump`(wfn, fname='INTDUMP', oe_ints=None)

  Save integrals to file in FCIDUMP format as defined in Comp. Phys. Commun. 54 75 (1989) Additional one-electron integrals, including orbital energies, can also be saved. This latter format can be used with the HANDE QMC code but is not standard.

  Returns: | None
  Raises: | ValidationError when SCF wavefunction is not RHF

  Parameters:

  - wfn (`Wavefunction`) – set of molecule, basis, orbitals from which to generate cube files
  - fname – name of the integrals file, defaults to INTDUMP
  - oe_ints – list of additional one-electron integrals to save to file.

  So far only EIGENVALUES is a valid option.

  Examples: |

      >>> # [1] Save one- and two-electron integrals to standard FCIDUMP format
      >>> E, wfn = energy('scf', return_wfn=True)
      >>> fcidump(wfn)

      >>> # [2] Save orbital energies, one- and two-electron integrals.
      >>> E, wfn = energy('scf', return_wfn=True)
      >>> fcidump(wfn, oe_ints=['EIGENVALUES'])