[molpro-user] Counterpoise correction for ion-molecular complexes

Yang, Shengfu F. (Dr.) sfy1 at leicester.ac.uk
Mon Feb 1 16:00:42 GMT 2010

Dear All,

Grant is probably right. The error information comes out as following:

The number of valence orbitals is .le. 0.
 One possible cause of this is that there are no orbitals available, ie you might have forgotten
 to do a Hartree-Fock calculation. Another possiblity is that the number of electrons is .le. half
 the number of uncorrelated core orbitals.

I have mistyped in the example, where a Na should be used instead of Li (dummy, Li; ==> dummy, Na).

What do I need to do in order to correlate all electrons? Grant indicated that the basis set for Na should be changed. Do I need to do anything more than that?



-----Original Message-----
From: Grant Hill [mailto:jghill at wsu.edu] 
Sent: 01 February 2010 15:30
To: Yang, Shengfu F. (Dr.)
Cc: molpro
Subject: Re: [molpro-user] Counterpoise correction for ion-molecular complexes

By default MOLPRO employs the frozen core approximation. This means that Li+ has no electrons to correlate in the CCSD(T) calculation. 

You could try to remedy this by correlating all electrons, but you will probably need to change your basis set.



On 1 Feb 2010, at 04:20, Yang, Shengfu F. (Dr.) wrote:

> Dear All,
> I have got a problem with the counterpoise correction for ion-molecular complex. For example, part of the input file is: (Na+He)
> {rhf; wf, 12,1, 0);
> rccsd(t);
> E1 = energy;
> dummy, He;
> {rhf;wf,10,1,0}
> rccsd(t);
> E2 = energy;
> dummy, Li
> hf;
> ccsd(t);
> E3 = energy;
> dummy;
> ....
> The error is always something like "there is no obital ...." for the counterpoise correction of Li+. Can I ask what the solution is for this problem?
> Thanks a lot for your help!
> Sincerely Yours,
> Dr. Shengfu YANG
> -------------------------
> Department of Chemistry
> University of Leicester
> Leicester LE1 7RH
> UK
> Tel: +44-116 252 2127
> Fax: +44-116 252 3789
> -------------------------
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