BSSE monomers with different multiplicity


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Hello!

I am trying to compute a simple CCSDT computation and I want to take into account the BSSE correction. My system is CH4 + H and I describe two different monomers. The first one is the methane and the sond one is the hydrogen with 1 electron. Soi, the 2 monomers have 2 different multiplicity.

When I am trying to compute this input file:

geometry units angstrom
  symmetry c1
  C    8.77882    4.09466    8.18421
  H    9.37839    4.74587    7.64094
  H    8.17915    3.55170    7.53275
  H    9.37839    3.44344    8.72748
 H    8.478984    4.366134    8.509940
 H    7.920094    4.872164    9.117099

 end

 charge 0

 basis
  H library cc-pvtz
  C library cc-pvtz
  bqH library H cc-pvtz
  bqC library C cc-pvtz
 end

 BSSE
 MON first 1 2 3 4 5
 MON second 6
 END

 scf
 doublet; rohf
 end

 TCE
 scf
 ccsd(t)
 END

 task tce energy
 


The associated output is :

 scf: no. of closed-shell electrons is not even!        1
 ------------------------------------------------------------------------
 ------------------------------------------------------------------------
  current input line :
    50:  task tce energy
 ------------------------------------------------------------------------
 ------------------------------------------------------------------------
 There is an error in the input file


I know that the problem is the description of 2 monomers but How can I describe the multiplicity of monomer in the input file? Do I need to make the Counterpoise correction manually?

If I do not add the scf module, I have the same output for the singlet monomer.


In advance, thank you!
Guillaume

Forum Regular
Hi Guillaume,

I have put a fix in for this problem. The code already has some facilities for other features in BSSE calculations but there was no input mechanism to specify these things. I have uploaded a patch for this. Note that this patch is relative to the NWChem-6.3 release code (i.e. without the recent patch for BSSE TDDFT calculations). Please apply the following patch:

1) cd $NWCHEM_TOP/src/task
2) wget http://nwchemgit.github.io/images/Mult-bsse.patch.gz
3) gzip -d Mult-bsse.patch.gz
4) patch -p0 < Mult-bsse.patch
5) recompile

The input that you want for the BSSE block is

 BSSE
MON first 1 2 3 4 5
MON second 6 mult 2
END

The singlet multiplicity is the default so you don't need to specify that for the first monomer.

Best wishes, Huub

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Hi,

Thank you very much for the answer! Unfortunatly, I compute on NWCHEM version 6.1. I am going to try to update to the version 6.3...

I will make a feed back when i will work on NWCHEM 6.3...

Guillaume


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