[molpro-user] CCSd(T) with core

[Kirk Peterson]

Dear Wafaa,

in principle the core directive as you've shown it only affects the uccsd(t) calculation and not the rhf step, which is where your job is failing. So without any other info I would say your optimization has taken a step to a geometry where the rhf is struggling to converge.  Inspection of your log file (not the out file) may be helpful.  Perhaps you could attach your input file?  Note that when correlating the core electrons you should change your basis set to one that is designed for this purpose, e.g., cc-pCVTZ or cc-pwCVTZ.

regards,

Kirk

On Feb 27, 2010, at 10:10 AM, Wafaa Fawzy wrote:

> Hi All,
> I ran optimization calculations that converged without the core electrons being correlated.  I repeated the same job with the option core: “uccsd(t);core”  but the optimization does not converge, I get an error saying : no convergence, the problem occurs in rhfpro”. 
> In my calculations, it is important to get accurate correlation energy.   Does anyone has an explanation or suggestions for solving the problem?
> Thanks in advance,
> Wafaa Fawzy
> Dept. of Chem.
> MSU
>  
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