[molpro-user] DF-LCCSD(T) with core electrons, again

[Tatiana Korona]

Dear Edmond,

"Deleting projected core orbital" concerns PAOs (i.e. virtual orbitals), not 
LMOs (i.e. occupied orbitals). If you have Li+, then you have only one occupied 
orbital for lithium, i.e. 1s(Li) and this is the orbital, which you can see in 
the orbital domain list in your output, so everything is OK.

Best wishes,

Tatiana


On Tue, 20 Sep 2016, Lee E.P.F. wrote:

> Dear MOLPRO users,
>
> Since I sent the email below, I have received no reply so far. Does any one have any thoughts/advice on core correlation with DF-LCCSD(T) ?
>
> Sorry to trouble you again. Any helps will be greatly appreciated. Many, many thanks in advance.
>
> Best Wishes,
> Edmond
> ________________________________________
> From: Lee E.P.F.
> Sent: 06 September 2016 22:14
> To: molpro-user at molpro.net
> Cc: ramchemi at intnet.mu; hbhakhoa at gmail.com; lyd.rhyman at gmail.com; Dyke J.M.
> Subject: re: DF-LCCSD(T) with core electrons
>
> Dear MOLPRO users,
>
> We want to use the DF-LCCSD(T) method to do some calns on some large alkali metal complexes. For example, with Li complexes, Li is usually Li+ in the complex. In this connection, the formally Li 1s2 core electrons are now become valence. We therefore have employed the cc-pwCVDZ basis set for Li and try to include Li 1s2 in the correlation by using the core key word. In our case, the default core is 22. We have checked that orbital 22.1 is Li 1s2 from the DF-HF output. So, we use core 21 with DF-LCCSD(T). However in the output, we have
>
> Deleting projected core orbital  826.1 (LI 1s)   Norm=  0.27D-02
>
> and also
>
> Ranking of atoms according to Loewdin charges
>
> Orbital domains
>
>   Orb.   Atom     Charge      Crit.
>  22.1    9 C       1.02       0.000
>         12 H       0.67       0.989
>  23.1    9 C       1.02       0.000
>         10 H       0.66       0.988
>  24.1    9 C       1.01       0.000
>         11 H       0.66       0.988
> etc.
>
> In the orbital domain, the only Li orbital included is
>
>  53.1   60 LI      1.88       0.989
>
> Have the Li 1s2 electrons been properly correlated ? Can a local correlation method deal with core electrons generally and/or in the case of Li+ specifically ? In the case of Li+, the Li 1s2 e's may be considered as quite deep down, but for heavier alkali metal, it has been shown that, e.g. for Na+, 2s2 2p6 are important. Would using just the core keyword deal with all situations ? Many thanks for your advice in advance.
>
> Best Regards,
> Edmond Lee
>
>
> ________________________________________
> From: Dyke J.M.
> Sent: 23 August 2016 11:42
> To: Lee E.P.F.
> Subject: FW: M(Me4cyclen)Solv+ project (Single point calculations)
>
> From: Prof Ponnadurai Ramasami [mailto:ramchemi at intnet.mu]
> Sent: 19 August 2016 12:14
> To: Dyke J.M.; jmdyke99 at gmail.com
> Cc: 'Lydia Rhyman'; hbhakhoa at gmail.com
> Subject: FW: M(Me4cyclen)Solv+ project (Single point calculations)
>
> Dear John,
>
> Please find attached files relevant to the single point computations.
>
> Kind regards,
> Ramasami
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>

Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, POLAND