[molpro-user] How to alter the active space

[Kirk Peterson]

John,

as an alternative to Gaussian's alter card, you can use the rotate  
command in Molpro which
allows one to do 2x2 rotations among individual orbitals. Setting the  
rotation angle to 90 deg.
corresponds to an orbital swap, e.g.,  rotate,5.1,4.1,90   switches  
orbitals 5 and 4 in symmetry 1. You
can have several rotate directives in a given rhf, ci, multi, or ccsd  
calculation (just place it somewhere
after or around your orbital directive).

hope that helps,

-Kirk

On Apr 25, 2008, at 9:03 AM, John Payton wrote:
> Dear MolPro Users and Authors,
>
> I'm relatively new to Molpro and trying to run some simple CASSCF
> calculation on benzene as to teach myself. However, I'm have an issue
> with trying to achieve a 6/6 active spaces (ie, pi-system of benzene).
> HF/6-31g* places the pi orbitals at HOMO-4, HOM0-1, HOMO, LUMO,
> LUMO+1, LUMO+8. Obviously, just setting occ,24;closed,18;wf,42,1,0
> will not give me my desired active space. I'm more familiar with using
> Gaussian and MolCas, and those programs use an alter card to change
> the order of the orbitals. However, Molpro doesn't seem to have this
> function. I see in the manual the con card. I have used it
> successfully, yet it seems I'm limited only to the configuration I
> select. I want a full CI in my desired active space. How can I achieve
> this? Any suggestion will be greatly appreciated.
>
> Thank You,
> John
>
>
> John L. Payton
> Ph.D. Candidate
> Simpson Group
> Department of Chemistry
> Case Western Reserve University
> 10900 Euclid Avenue
> Cleveland, Ohio  44106-7078
>