[molpro-user] UCCSD(T)-reg

[Gerald Knizia]

Dear Tatiana,
oh, right. Thanks for pointing this out. I think I have also seen this a
while back, but I thought it was fixed at some point by adjusting the
default thresholds for big bases, but maybe not (I am not sure). It is
certainly something important to consider when using diffuse basis sets.
I will add it to the "Handling Difficult Cases" section. Thanks again!

Best wishes,
Gerald

On Sun, 2015-12-20 at 18:20 +0100, Tatiana Korona wrote:
> Hi,
> 
> Sometimes it helps to tighten thresholds for integrals, especially if very 
> diffuse functions are used in an orbital basis set. It happened to me several 
> times that default 1.E-12 was too loose for some augmented or doubly-augmented 
> cases.
> 
> Best wishes,
> 
> Tatiana
> 
>   On Sun, 20 Dec 2015, Gerald Knizia wrote:
> 
> > Dear Mano Priya,
> > the recommended method is to get RHF to converge. Our RHF is *very*
> > stable, and if it does not converge (with enabled level shifts), then
> > probably something went wrong with either the system or state you are
> > computing. Ignoring this error is not recommended, unless you are
> > absolutely sure what you are doing.
> >
> > A number of hints on SCF convergence errors are given in the section
> > "Handling difficult cases: When SCF does not converge" of "The SCF
> > Program" of the Molpro Manual. E.g., for Molpro 2012: Chapter 16.10,
> > https://www.molpro.net/info/2012.1/doc/manual/node172.html
> >
> > Without further information, there is, unfortunately, little to say
> > about this.
> >
> > Best wishes,
> > Gerald
> >
> >
> >
> > On Sat, 2015-12-19 at 12:04 +0530, Mano Priya wrote:
> >> Dear Molpro developers,
> >>                                   I am trying to run single point
> >> calculations in UCCSD(T) . I end up with below error.
> >>
> >>
> >>  ?Error: RHF not converged. This error exit can be avoided using the
> >> IGNORE_ERROR option on the ORBITAL directive
> >>
> >>
> >> I am in need of your suggestions, how to rectify the above error to
> >> run single point calculation.
> >>
> >>
> >> With regards
> >> A.Mano priya,
> >>
> >>
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> >
> >
> >
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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
>