Necessary input to SIRIUS

In order for DALTON to perform a calculation for a given wave function a minimum amount of information is required. This information is collected in the **WAVE FUNCTIONS input module. Fig. 6.1 collects the most essential information.

Figure 6.1: Necessary input information for determining the wave function.

   Calculation type(s): RHF, MP2, CI, MCSCF, CC.

   Number of symmetries (needed only for MCSCF wave functions)
   If MCSCF or CI calculation then
      Symmetry of wave function.
      Spin multiplicity of wave function.
   else if one open shell RHF
      Symmetry of open shell, doublet spin multiplicity
   else
      Totally symmetric, singlet spin multiplicity
   end if

   Number of basis orbitals.
   Number of molecular orbitals.

   Number of inactive orbitals in each symmetry.
   If high-spin open shell RHF then
      Number of singly occupied orbitals in each symmetry
   else if MCSCF or CI calculation then
      Number of active electrons.
      If CAS calculation desired then
         Number of active orbitals in each symmetry.
      else if RAS calculation desired then
         Number of active orbitals in RAS1 space in each symmetry.
         Number of active orbitals in RAS2 space in each symmetry.
         Number of active orbitals in RAS3 space in each symmetry.
         Limits on number of electrons in RAS1 and RAS3.
      end if
   end if

   if not MP2 then convergence threshold.

   how to begin the calculation (initial guess).