program scf BEGIN_DOC ! ! The :ref:`scf` program performs *Restricted* Hartree-Fock ! calculations (the spatial part of the |MOs| is common for alpha and beta ! spinorbitals). ! ! It performs the following actions: ! ! #. Compute/Read all the one- and two-electron integrals, and store them ! in memory ! #. Check in the |EZFIO| database if there is a set of |MOs|. ! If there is, it will read them as initial guess. Otherwise, it will ! create a guess. ! #. Perform the |SCF| iterations ! ! For the keywords related to the |SCF| procedure, see the ``scf_utils`` ! directory where you will find all options. ! ! At each iteration, the |MOs| are saved in the |EZFIO| database. Hence, ! if the calculation crashes for any unexpected reason, the calculation ! can be restarted by running again the |SCF| with the same |EZFIO| ! database. ! ! To start again a fresh |SCF| calculation, the |MOs| can be reset by ! running the :ref:`qp_reset` command. ! ! The `DIIS`_ algorithm is implemented, as well as the `level-shifting`_ ! method. If the |SCF| does not converge, try again with a higher value of ! :option:`level_shift`. ! ! .. _DIIS: https://en.wikipedia.org/w/index.php?title=DIIS ! .. _level-shifting: https://doi.org/10.1002/qua.560070407 ! END_DOC call create_guess call orthonormalize_mos call run end subroutine create_guess implicit none BEGIN_DOC ! Create a MO guess if no MOs are present in the EZFIO directory END_DOC logical :: exists PROVIDE ezfio_filename call ezfio_has_mo_basis_mo_coef(exists) if (.not.exists) then if (mo_guess_type == "HCore") then mo_coef = ao_ortho_lowdin_coef TOUCH mo_coef mo_label = 'Guess' call mo_as_eigvectors_of_mo_matrix(mo_one_e_integrals, & size(mo_one_e_integrals,1), & size(mo_one_e_integrals,2), & mo_label,1,.false.) call nullify_small_elements(ao_num, mo_num, mo_coef, size(mo_coef,1), 1.d-10) SOFT_TOUCH mo_coef mo_label else if (mo_guess_type == "Huckel") then call huckel_guess else print *, 'Unrecognized MO guess type : '//mo_guess_type stop 1 endif endif end subroutine run BEGIN_DOC ! Run SCF calculation END_DOC use bitmasks implicit none integer :: i_it, i, j, k mo_label = "Orthonormalized" call Roothaan_Hall_SCF call ezfio_set_hartree_fock_energy(SCF_energy) end