[molpro-user] RHF Doesn't converge

[Grant Hill]

Dear Auila,

The answer to your question depends on what type of multi calculation you would like to run. Do you wish to run a full valence CAS to attempt to identify the lowest state, or do you want a single CSF to ‘mimic’ a HF calculation?

One way of determining the active space (via occ and closed cards) is to use the output from one of your failed calculations - you should see a section such as:

 NUMBER OF CORE ORBITALS:          25   (  15A'  +  10A"  )
 NUMBER OF VALENCE ORBITALS:      112   (  61A'  +  51A”  )

Which should inform you that a full valence active space would have occ,76,61 and closed 15,10. This is obviously a huge active space and probably not what you want.

However, are you sure that you want the wave function symmetry to be 1 (i.e., A’)? I haven’t given it much thought, but it’s possible that this system is A”.

Best wishes,

Grant



> On 11 May 2015, at 08:21, Aulia Sukma Hutama <hutamaaulia at gmail.com> wrote:
> 
> Dear Molpro User,
> 
> I am trying to calculate the atom-molecule system using CCSD(T). However, the RHF doesn't converge. I have followed the tutorial to use the levelshift, freezing occupation orbital, increasing DIIS, start from smaller basis set, but none of them working. Maybe, the last thing is use the MCSCF. I have browsed to this mailing list and found this thread.
> 
> http://www.molpro.net/pipermail/molpro-user/2010-May/003756.html
> 
> But, for me it is not clear how to use this multi card. How I should specify the number of occ, closed and/or frozen etc. I also have browsed the tutorial, but I can't get any reference how I should put these number for my system. What I want is the ground state of the system. Are there any tips? Here I copy the input file. Your helps are much appreciated.
> 
> PS: This geometry is correct. I want to calculate when the F atom is a little bit far away from the coronene (C24H12) molecule. The symmetry of the system is Cs.
> 
> Regards,
> 
> Aulia
> 
> ***,Coronene-F ROCCSD(T)
> 
> memory,3000,M
> 
> geometry={
> 
> 37
> 
> Coronene-Fluorine
> 
>  C                  0.00377700    3.61857400    1.25075200
> 
>  C                 -0.02396100    2.93088400    0.00000000
> 
>  C                 -0.08211700    1.51041400    0.00000000
> 
>  C                 -0.11293700    0.79641300    1.23792200
> 
>  C                 -0.08701600    1.50742500    2.47136100
> 
>  C                 -0.02670100    2.93338200    2.44086200
> 
>  C                 -0.11293700    0.79641300   -1.23792200
> 
>  C                 -0.16984000   -0.62887500    1.23917000
> 
>  C                 -0.16984000   -0.62887500   -1.23917000
> 
>  C                 -0.24758200   -2.77602400    0.00000000
> 
>  C                 -0.28257300   -3.45871800    1.24901100
> 
>  C                 -0.26699800   -2.76707400    2.43670500
> 
>  C                 -0.20784700   -1.33970000    2.46852300
> 
>  C                 -0.18160600   -0.60565200    3.68799700
> 
>  C                 -0.12195100    0.76998800    3.68887100
> 
>  H                 -0.10046600    1.31715800    4.63456200
> 
>  H                 -0.20741200   -1.15448400    4.63252800
> 
>  H                  0.05006000    4.71037200    1.24666000
> 
>  H                 -0.00446400    3.47705500    3.38855400
> 
>  H                 -0.32238000   -4.55037800    1.24866000
> 
>  H                 -0.29501100   -3.30909800    3.38527200
> 
>  C                  0.00377700    3.61857400   -1.25075200
> 
>  C                 -0.02670100    2.93338200   -2.44086200
> 
>  C                 -0.08701600    1.50742500   -2.47136100
> 
>  H                  0.05006000    4.71037200   -1.24666000
> 
>  H                 -0.00446400    3.47705500   -3.38855400
> 
>  C                 -0.12195100    0.76998800   -3.68887100
> 
>  C                 -0.18160600   -0.60565200   -3.68799700
> 
>  C                 -0.20784700   -1.33970000   -2.46852300
> 
>  H                 -0.10046600    1.31715800   -4.63456200
> 
>  H                 -0.20741200   -1.15448400   -4.63252800
> 
>  C                 -0.28257300   -3.45871800   -1.24901100
> 
>  H                 -0.32238000   -4.55037800   -1.24866000
> 
>  C                 -0.26699800   -2.76707400   -2.43670500
> 
>  H                 -0.29501100   -3.30909800   -3.38527200
> 
>  C                 -0.19755500   -1.34323500    0.00000000
> 
>  F                  2.50121600   -1.42473800    0.00000000
> 
> 
> 
> 
> 
> }
> 
> BASIS=CC-PVDZ
> 
> int;
> 
> {rhf;wf,165,1,1}
> 
> 
> 
> rccsd(t);  
> ---
> 
> 
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