[molpro-user] Convergence not reached for a CCSD iteration in CCSD(T) optimization

[wyb]

Dear MolPro users


I encountered a problem in the CCSD(T)/aug-cc-pVTZ optimization [but CCSD(T)/cc-pVTZ optimization can be achieved].
In one of the CCSD step, the "VAR (P)" can not be lowered below 1.0D-12 even I increase the maximum number of CCSD iterations to 300.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 ITER.   SQ.NORM   CORR.ENERGY TOTAL ENERGY  ENERGY CHANGE     DEN1      VAR(S)    VAR(P)     DIIS     TIME
   1      1.25279637    -0.50350353  -116.32933471    -0.03743526    -0.02192105  0.19D-02  0.50D-02  1  1     8.30
    .               .                        .                      .                         .                        .                    .               .        .    .        .
    .               .                        .                      .                         .                        .                    .               .        .    .        .
    .               .                        .                      .                         .                        .                    .               .        .    .        .

  97      1.28543234    -0.50769672  -116.33352790    -0.00000000     0.00000000  0.11D-14  0.17D-10  6  2   336.65
  98      1.28543234    -0.50769672  -116.33352790    -0.00000000    -0.00000000  0.94D-15  0.18D-10  6  6   340.07
  99      1.28543234    -0.50769672  -116.33352790     0.00000000     0.00000000  0.94D-15  0.18D-10  6  2   343.52



 Norm of t1 vector:      0.07197772      S-energy:     0.00000000      T1 diagnostic:  0.01138068
                                                                       D1 diagnostic:  0.03667313

?CONVERGENCE NOT REACHED AFTER MAX. ITERATIONS
------------------------------------------------------------------------------------------------------------------------------------------------------------

I think the possible way to solve this problem is to promote the convergence of the "VAR (P)" item using certain keyword(s) or to reduce the criterion a little bit (for example to 1.0D-11), but I can not find the related keyword(s) in the manual. Maybe I did not catch what the manual says.


Can anyone tell me how to sovle this problem?


Thank you in advance!


Best,


Yan-Bo Wu
---------------------------------------
Institute of Molecular Science
Shanxi University
Taiyuan, 030006, Shanxi Province, China.



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