Forcing canonical occ. and virt. MOs for NEVPT2 calculations

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Max
Posts: 8
Joined: 16 Jan 2014, 17:27
First name(s): Latevi
Middle name(s): Max
Last name(s): Lawson Daku
Affiliation: University of Geneva
Country: Switzerland

Forcing canonical occ. and virt. MOs for NEVPT2 calculations

Post by Max » 11 Mar 2016, 11:50

Dear Dalton users,


I'm performing NEVPT2 calculations and would like to ensure that canonical occupied
and virtual MOs are really being used during these calculations. In my input, (please
see the attached file), I'm using the ".TRACI" option, which by default is controlled by
the program. At the end of the CASSCF calculations the following message is printed

SIRCAN: canonical/natural orbitals and corresponding
CI coefficents saved on the Sirius restart file.

I guess these are those data that are going to be used in the NEVPT2 calculations. The
above message is also printed when I do not set the ".TRACI" option for the NEVPT2
calculations. So I also guess the transformation is done by default. Is this correct ?
Is the ".TRACI" option the one to use? Is there an other one?

I thank you in advance for your help.

Best regards,
Max
Attachments
co3_nch.d2h.b1t_cas5_nevpt2.ls.out
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hjaaj
Posts: 371
Joined: 27 Jun 2013, 18:44
First name(s): Hans Jørgen
Middle name(s): Aagaard
Last name(s): Jensen
Affiliation: Universith of Southern Denmark
Country: Denmark

Re: Forcing canonical occ. and virt. MOs for NEVPT2 calculat

Post by hjaaj » 19 Mar 2016, 13:47

Dear Max,

1) Yes, the orbitals used in NEVPT2 are always the final orbitals from the MCSCF optimization. The program will tell you when it does not update orbitals (typically seen after a RASSCF calculation where it is not possible to transform the CI-vector to natural orbital basis).
2) ".TRACI" and default is currently the same. You only need to specify something if you want e.g. pseudo-canonical active orbitals, i.e. orbitals diagonalizing the "FC+FV" Fock matrix for the active-active block (default is natural orbitals).

-- Hans Jørgen.

Max
Posts: 8
Joined: 16 Jan 2014, 17:27
First name(s): Latevi
Middle name(s): Max
Last name(s): Lawson Daku
Affiliation: University of Geneva
Country: Switzerland

Re: Forcing canonical occ. and virt. MOs for NEVPT2 calculat

Post by Max » 21 Mar 2016, 16:48

Dear Hans,

Thanks a lot for your kind e-mail with clear and detailed explanations!

Best regards,
Max

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