:orphan:
 

GOSCIP
======

Let us remind first that DIRAC
uses the so-called averaged SCF scheme, which means that all
the configurations belonging to the reference space receive the same
weight. 

In the case when one (or few) of the states from the reference
space is (or are) more important then others, than the large open-shell space can lead to
dis-balanced treatment and therefore to higher SCF energies than those obtained with a smaller
reference space.

The "better" SCF configuration is that one giving the lowest total energy.
Upon suitable averaged open-shell SCF occupation one can perform complete open-shell CI (COSCI)
calculatons, one example is given below.


Sample inputs
-------------

Calculate the spin-orbit components of the 2P ground state of the
fluorine atom using a COSCI wavefunction. This will represent the
"uncorrelated" result since the CI will merely give the energies of the
individual determinants in this simple case. 

The same calculation can
also be done automatically by specifying :ref:`WAVE_FUNCTION_.RESOLVE`
in the :ref:`**WAVE FUNCTION` section of the input.

The full calculation is given as input example of the  *cosci_energy*  test:

::

     &GOSCIP NELEC=5, IPRNT=1 &END
     &POPANA THRESH=1.0D-4, DEGEN=1.0D-12, SELPOP=50.0 &END

**NOTE: In the developer's version the first line reads as**

::

     &GOSCIP NELACT=5, IPRNT=1 &END
     &POPANA THRESH=1.0D-4, DEGEN=1.0D-12, SELPOP=50.0 &END