[molpro-user] How is Pople correction calculated.

Lorenzo Lodi l.lodi at ucl.ac.uk
Wed Apr 6 18:21:20 CEST 2016

Hello Dawid,
the Pople correction in Molpro is computed in the `standard' way (see
eg. formula 3.32 at page 60 in
http://www.tampa.phys.ucl.ac.uk/ftp/eThesis/LorenzoLodi2009.pdf) and as
'number of electrons' molpro takes the number of correlated electrons
(not necessarily `active': correlated but inactive electrons also count;
ie, correlated core electrons are also counted). Maybe Columbus always
uses the total number of electrons instead? If this is what it does it
looks unreasonable to me.


Il 30/03/2016 15:44, Dawid das ha scritto:
> Dear Molpro Experts,
> I have calculated MR-CISD excitation energies with Molpro 2012.1 and
> Columbus 7 and  I see
> some major discrepancies in case of MR-CISD EEs including Pople correction.
> Could you explain shortly how this correction is calculated in Molpro?
> In Columbus I can
> see and information that
>  pople ci energy extrapolation is computed with 32 correlated electrons.
> even though I have used only 6 electrons in my active space. Is it
> possible that in Molpro
> a different number of correlated electrons is used?
> Best regards,
> Dawid Grabarek

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