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