scfguess
========

This option defines the arguments for searching minimum energy crossing point (MECP).

.. contents::
   :local:

.. option:: num_steps

   .. list-table::
      :stub-columns: 1
      :widths: 5 20
   
      * - Value
        - An integer
      * - Default
        - ``200``

The maximum number of MECP search.

.. option:: energy_cov

   .. list-table::
      :stub-columns: 1
      :widths: 5 20
   
      * - Value
        - A real number 
      * - Default
        - ``1.E-5``

  The energy difference convergence threshold. When ``energy_cov``, ``grad_cov``, and ``dr_cov`` are all met, the MECP will be set to be converged.

.. option:: grad_cov

   .. list-table::
      :stub-columns: 1
      :widths: 5 20
   
      * - Value
        - A real number 
      * - Default
        - ``1.E-3``

  The gradient convergence threshold. When ``energy_cov``, ``grad_cov``, and ``dr_cov`` are all met, the MECP will be set to be converged.

.. option:: dr_cov

   .. list-table::
      :stub-columns: 1
      :widths: 5 20
   
      * - Value
        - A real number 
      * - Default
        - ``1.E-3``

  The displacement convergence threshold. When ``energy_cov``, ``grad_cov``, and ``dr_cov`` are all met, the MECP will be set to be converged.


.. option:: orb1

  This defines the electronic configuration of state 1. The format is:
  
  ``orb num_electrons spin_multiplicity  alpha_MO_indices : beta_MO_indices``
  
  There can be arbitrary number of ``orb1``, but all orbitals must be included once and only once.
  They are the same as ``orb`` in ``scfguess``. See :doc:``scfguess``.

.. option:: orb2

  This defines the electronic configuration of state 2. The format is:
  
  ``orb num_electrons spin_multiplicity  alpha_MO_indices : beta_MO_indices``
  
  There can be arbitrary number of ``orb2``, but all orbitals must be included once and only once.
  They are the same as ``orb`` in ``scfguess``. See :doc:``scfguess``.

.. option:: frag1

    This defines the fragmentation of state 1. The format is:
  
  ``frag num_electrons spin_multiplicity atom_range``
  
  There can be arbitrary number of ``frag1``, but all atoms must be included once and only once.
  They are the same as ``frag`` in ``scfguess``. See :doc:``scfguess``.

.. option:: frag2

    This defines the fragmentation of state 1. The format is:
  
  ``frag num_electrons spin_multiplicity atom_range``
  
  There can be arbitrary number of ``frag2``, but all atoms must be included once and only once.
  They are the same as ``frag`` in ``scfguess``. See :doc:``scfguess``.

  .. HINT::
    When ``frag1/2`` and ``orb1/2`` are defined simultaneously, ``orb1/2`` will be considered in priority.