##master-page:HelpTemplate
##master-date:Unknown-Date
#format wiki
#language en
#Please change following line to BDF module name

= MCSCF =
<<TableOfContents(4)>>

{{{
Multi-configurational self consistent field program.
}}}
== General keywords ==
=== Close ===
{{{#!wiki
  Number of inactive orbitals in each irreps.
}}}
Example:


=== Active ===
{{{#!wiki
  Number of active orbitals in each irreps.
}}}
Example:

=== actel ===
{{{#!wiki
  Number of active electrons in active space.
}}}
Example:

=== RootPrt ===
{{{#!wiki
  Print the target state (root) energy for calculating numerical gradient of this state in numgrad module, default is 1.
}}}
Example:
{{{
RootPrt
 3   # the third state (root) energies will be printed.
}}}

=== Symmetry ===
{{{#!wiki
  Symmetry of the target state.
}}}
Example:

=== Spin ===
{{{#!wiki
  Spin multiplicity. 2S+1
}}}
Example 1:
{{{
Spin
 1   # singlet
}}}

Example 2:
{{{
Spin
 2  # doublet
}}}


=== Roots ===
{{{#!wiki
Three lines should be provided.
Line 1: Two integrals. The first is number of averaged states and the second number of states calculated in CI.
Line 2: which states should be averaged
Line 3: weight of states in state-average calcualtion
}}}
Example:
{{{
Roots
3  4     # 3 states will be averged, 4 states will be calculated
1 2 3   # States 1 2 3 will be averged
1 1 1    # equal weight for each state
}}}

=== RAS ===
{{{#!wiki
several lines should be provided for controlling RASSCF calculations.
Line 1: number for different RAS spaces, like RAS1, RAS2, RAS3, ...., the index for CAS space which all electron excitations are allowed.
Line 2: allowed excitation electron number of the double occupied RAS spaces or all electrons of CAS or allowed accept electrons of unoccupied RAS space. 
From Line 3 to Line (RAS spaces number plus 2) set active orbital with symmetry of these RAS spaces.
}}}
Example:
{{{
ras
2 2  ! there are two RAS spaces, the second RAS space is CAS space.
2 6  ! first RAS space (RAS1) allows maximum 2 electrons are excited. second RAS space (RAS2) allow all of 6 electrons are excited. 
5 0 0 3  ! active orbitals of each irreps of RAS1
0 2 3 1  ! active orbitals of each irreps of RAS2.
}}}
Comment:
{{{
   With keyword 'RAS' setting, keywords 'active' is useless and can be missing.
}}}



=== MixCI ===
{{{#!wiki
Four lines should be provided for controlling state average CASSCF calculations with different spin and space symmetries of CAS-CI.
Line 1: number for different types of CI.
Line 2: spin multiplicity for each type of CI.
Line 3: averaged state number for each type of CI.
Line 4: irreducible representation number for each type of CI.
}}}
Example:
{{{
MixCI
  3      # number for three types of CI.
1 3 5    # singlet, triplet and quintet for three types of CI, respectively.
3 1 2    # three, one and two averaged states for three types of CI, respectively, sum of them must be equal to that setting in 'Nroots'.
1 4 3    # first, fourth, third irreducible representation for three types of CI, respectively.
}}}
Comment:
{{{
   With keyword 'MixCI' setting, keywords 'spin' and 'symmetry' are useless and can be missing.
}}}

=== guess ===
{{{#!wiki
  Initial molecular orbitals reading.
}}}

Notice:
{{{
  Guess : hforb  is default with SCF MOs as initial MOs from TMPDIR by the unformatted File hforb.
  Guess : mcorb  is set with recent MCSCF MOs as initial MOs from TMPDIR by the unformatted File mcorb.
  Guess : inporb is set with recent MCSCF MOs as initial MOs from WORKDIR by the formatted File inporb, canorb, scforb in turn.
  Guess : hcore  is set with Nuclear core Hamiltonian as initial MOs.
  Guess : huckel is set with Extend Huckel Hamiltonian as initial MOs.
}}}


Example 1:
{{{
Guess
 hforb   # read SCF MOs from scratch file, which is default.
}}}

Example 2:
{{{
Guess
 hcore   # with Nuclear core Hamiltonian as initial MOs.
}}}

Example 3:
{{{
Guess
 inporb   # read from local files '$Project.inporb', '$Project.canorb', and '$Project.scforb' in turn to find guess MOs.
}}}

Example 4:
{{{
Guess
 mcorb   # read CASSCF MOs from scratch file.
}}}

=== direct ===
{{{#!wiki
  MCSCF calculation with one direct CI step in each micro-iteraction, which may be useful in large CI system, default is .false..
}}}

=== molden ===
{{{#!wiki
  Output MCSCF orbital into Molden format file.
}}}

=== CIONLY ===
{{{#!wiki
  Only CI optimization is done.
}}}

=== QUASI ===
{{{#!wiki
  Use quasi-Newton method for orbital optimization, like Second-Order SCF method, which requires less Memory and has fast MOints Transformation than Second-Order method, like Newton-Raphson method.
}}}

=== NOGRAD ===
{{{#!wiki
  Do not save orbital Hessian to disk, which is used for analytical gradients. Default is not input this parameter, so that it can be saved. 
}}}



== Parameter keywords ==

=== MACIT ===
{{{#!wiki
  Maximum step of Macro iteration. Default : 20
}}}
Example:

=== MICIT ===
{{{#!wiki
  Maximum step of Micro iteration. Default : 50
}}}
Example:

=== CIITER ===
{{{#!wiki
  Maximum step of CI Davidson iterations. Default : 50
}}}
Example:

=== NCISAVE ===
{{{#!wiki
  Maximum dimension of CI Hamiltonian Matrix which can be saved on core memory. Default : 20000
}}}
Example:

=== NODE ===
{{{#!wiki
  Maximum DRT node number. The default value is 300000.
}}}
Example:

=== WEI ===
{{{#!wiki
  Maximum DRT WEI number. The default value is 5000000.
}}}
Example:

=== PLOOP ===
{{{#!wiki
  Maximum partial LOOP number. The default value is 1000000.
}}}
Example:

=== NREF ===
{{{#!wiki
  Maximum Ref number. The default value is 10000.
}}}
Example:

=== NVFF ===
{{{#!wiki
  Maximum two electron integral number of active space. The default value is 10000000.
}}}
Example:


=== THRESHMAC ===
{{{#!wiki
  Threshold of CI optimization. Default : 1.d-8
}}}
Example:

=== THRESORB ===
{{{#!wiki
  Threshold of orbital optimization. Default : 1.d-5
}}}
Example:

=== PRTCRI ===
{{{#!wiki
  Threshold of CI coefficient which will be printed to output file after MCSCF optimization. Default : 0.05
}}}
Example: