[molpro-user] UCCSD(T)-reg

Tatiana Korona tania at tiger.chem.uw.edu.pl
Sun Dec 20 18:20:54 CET 2015


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 

Best wishes,


  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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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

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