[molpro-user] NaCl CASSCF input

[Toru Shiozaki]

Dear Natalie,
there are two problems in your input: 
i) you have HF inside the do loop. Near avoided crossing, HF does not give an appropriate starting guess for casscf
(if it converges at all). It is better instead to use the orbitals from the previous geometry.
ii) Either the orbitals 3 in irrep 2 and 3 need to be closed, or 4th orbitals should be included.

Perhaps it is informative if you compute full valence CASSCF (i.e., without occ and closed keywords)
and see the natural orbitals and its occupation numbers (put "gprint,civectors,orbitals" at the beginning of the input)

Try the input below:

> gprint,civectors,orbitals
> geometry={ Na; Cl Na r(i); }
> r=[1.5,1.6,1.7,1.8,1.9,2,2.2,2.4,2.6,2.8,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5,8,100] angstrom
> basis,cc-pVTZ
> do i=1,#r
> if (i.eq.1) hf
> {casscf; occ,9,3,3; closed,7,3,3; state,2;}
> enddo

Best wishes,
Toru

On Apr 15, 2011, at 11:48 AM, natalie harries wrote:

> Hi users,
> 
> I'm having some trouble fitting an input for CASSCF calculation on NaCl, 
> please see the input below
> 
> geometry={
> Na
> Cl Na rvalue
> }
> r=[1.5,1.6,1.7,1.8,1.9,2,2.2,2.4,2.6,2.8,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5,8,100] angstrom
> do i=1,#r
> rvalue=r(i)
> basis,cc-pVTZ
> gexpec,sm,ekin
> hf
> ehf(i)=energy
> {casscf
> occ,9,3,3
> closed,7,2,2
> state,2
> }
> eground(i)=energy(1),eexcited(i)=energy(2)
> {mrci;pspace,999;state,2}
> emrcig(i)=energy(1),emrcie(i)=energy(2)
> tx(i)=ekin(1)
> te(i)=ekin(2)
> dipolex(i)=-DMZ(1)
> dipolee(i)=-DMZ(2)
> widthx(i)=xx(1)
> widthe(i)=xx(2)
> enddo
> 
> I believe my occ and closed numbers are wrong, and I'm struggling with knowing how to pick the correct numbers,
> 
> thanks all
> Natalie
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