[molpro-user] Selection of certain orbitals to correlate

[Quan Phung]

Dear Prof. Kirk Peterson,

Thank you for your suggestion. Indeed, your way is more straightforward and
gives the same results as compared to mine.

Best regards,
Quan

On Sat, Nov 1, 2014 at 6:00 PM, Peterson, Kirk <kipeters at wsu.edu> wrote:

> Dear Quan,
>
> the much more straightforward route is to use the rotate command from
> within the ccsd(t) calculation itself and leave your hf input unchanged,
> e.g.,
>
> {ccsd(t)
> core,16,9,9,2,9,2,2,0
> rotate,9.1,16.1
> rotate,4.2,9.2
> rotate,4.3,9.3
> rotate,4.5,9.5
> maxit,50
> shift,1
> }
>
>
> best regards,
>
> -Kirk
>
>
> > On Oct 31, 2014, at 2:18 PM, Quan Phung <manhquank9 at gmail.com> wrote:
> >
> > Dear Molpro users,
> >
> > Let say I have HF orbitals of a molecule and I want to to CCSD(T) of
> this molecule.
> > Now I would like to correlate just some orbitals. including some valance
> (but not all valance) and some low-lying core orbitals. So I have to rotate
> the core orbitals with the valance orbitals that I do not want to correlate
> and do only one iteration. For example:
> >
> > {hf
> > wf,108,1,0
> > shift,-1.0,-0.5
> > maxit,1
> > start,2101,2
> > closed,18,9,9,3,9,3,3,0
> > occ,   18,9,9,3,9,3,3,0
> > rotate,9.1,16.1,90
> > rotate,4.2,9.2,90
> > rotate,4.3,9.3,90
> > rotate,4.5,9.5,90
> >
> > }
> > where 9.1, 4.2, 4.3, 4.5 are core orbitals and 16.1, 9.2, 9.3 and 9.5
> are valance orbitals that I do not want to correlate.
> > After that I do a CCSD(T) calculation based on this HF calculation.
> > {ccsd(t)
> > core,16,9,9,2,9,2,2,0
> > maxit,50
> > shift,1
> > }
> >
> > I would like to ask if it is make sense to do this?
> > I also notice that after rotation and do the HF calculation, the core
> orbitals (9.1, 4.2, 4.3, 4.5)  are now high-lying and have the energy equal
> the the energy of the valence orbitals that were rotated. I am not sure if
> this is correct. To be clear:
> > Before rotation (full HF calculation):
> > ORBITAL  9.1 (core)    eig=   -4.4491
> > ORBITAL 16.1 (valance) eig=   -0.9945
> >
> >
> > After rotation, HF one iteration:
> > ORBITAL  9.1 (valance)  eig=   -4.4491
> > ORBITAL 16.1 (core)     eig=   -0.9945
> >
> >
> > Best regards,
> > Quan
> >
> > _______________________________________________
> > Molpro-user mailing list
> > Molpro-user at molpro.net
> > http://www.molpro.net/mailman/listinfo/molpro-user
>
>
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