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50 lines
1.4 KiB
ReStructuredText
50 lines
1.4 KiB
ReStructuredText
.. _.fci.:
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.. program:: fci
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===
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fci
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===
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Selected Full Configuration Interaction with stochastic selection and PT2 .
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This program performs a CIPSI-like selected CI using a stochastic scheme for both
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the selection of the important Slater determinants and the computation of the PT2 correction.
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This CIPSI-like algorithm will be performed for the "n_states" lowest states of the variational space (see :option:`determinants n_det_max`)
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The fci program will stop when reaching at least one the two following conditions:
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* number of Slater determinant > "n_det_max" (see :option:`determinants n_det_max`)
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* |PT2| < "pt2_max" (see :option:`perturbation pt2_max`)
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The following other options can be of interest:
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If "read_wf" = False, it starts with a ROHF-like Slater determinant as a guess wave function.
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If "read_wf" = True , it starts with the wave function(s) stored in the EZFIO folder as guess wave function(s).
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(see :option:`determinants read_wf`)
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If "s2_eig" = True, it will systematically add all necessary Slater determinants in order
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to have a pure spin wave function with an :math:`S^2` value corresponding to "expected_s2".
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(see :option:`determinants s2_eig` and :option:`determinants expected_s2`)
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For excited states calculations, it is recommended to start with a :c:func:`cis` or :c:func:`cisd` guess wave functions
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for the "n_states", and to set "s2_eig" = True.
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File: :file:`fci/fci.irp.f` |