[molpro-user] How to avoid orbital mixing when changing symmetry

[Joaquim Jornet Somoza]

Thank you Seth !

However, I've found that is not so easy due to the number of occupated
orbitals.
Finally I've found a way to do it that works....(even if maybe it is not
the "proper" way...)

I've avoided the change of symmetry group... :).

At least, in my case, even with a low symmetry  HF or low CASSCF give good
orbitals (almost the same orbitals as the corresponding with high symmetry
group with the same level of theory). However, to fix the orbital mixing
using high CASSCF (i.e. more orbitals) I duplicated the computation : 1st.
without optimizing the wavefunction neither the orbitals (*dont,wvfn*), and
2nd. optimizing everything with diabatization (*diab*) taking as reference
the last "non-optimized" orbitals.

This form works to me....I hope this can help someone.

quim


2012/10/9 Seth Olsen <seth.olsen at uq.edu.au>

>  Try to use "diab" to maximize the overlap of the output orbitals onto
> the reference set.
>
> Seth Olsen, Ph.D.
> ARC Australian Research Fellow
> School of Mathematics & Physics
> The University of Queensland
> Brisbane, QLD 4072
> Australia
> +61 7 3365 2816
>
> On 09/10/2012, at 22:12, "Joaquim Jornet Somoza" <
> j.jornet.somoza at gmail.com> wrote:
>
>   Dear all,
>
> I would like to compute a energy surface for a molecule CASSCF level
> I started for the most symmetric geometry that belong into C2v group. I
> computed a small CASSCF(2,2) to get the proper orbitals and then moved to
> CASSCF(2,9).
> But when I change the geometry along the reaction coordinate the symmetry
> changes to C2 and the orbitals mix.
>
> I've found that it is possible using: dont,orbital --> which disable the
> orbital optimization, but it still mixes the orbitals.
>
> Someone has a solution?
> Thank you in advance.
>
> --
> Joaquim Jornet Somoza
> Postdoctoral Researcher                          email:
> j.jornet.somoza at gmail.com <quim.jornet at gmail.com>
> Dynamique Réactionnelle                         tel: 0033 46714 3914
> Institut Charles GERHARDT-CNRS 5253
> Université Montpellier 2
>
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>


-- 
Joaquim Jornet Somoza
Postdoctoral Researcher                          email:
j.jornet.somoza at gmail.com <quim.jornet at gmail.com>
Dynamique Réactionnelle                         tel: 0033 46714 3914
Institut Charles GERHARDT-CNRS 5253
Université Montpellier 2
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