[molpro-user] N2O CCSD(T)/cc-pVDZ calculation disagrees with NWChem

Gerald Knizia knizia at theochem.uni-stuttgart.de
Mon Mar 16 13:46:14 GMT 2009

On Monday 16 March 2009 10:42, Robert Hinde wrote:
> I'm trying to use the file below to compute the frozen-core
> CCSD(T)/cc-pVDZ energy for N2O.  The results that I get using
> Molpro version 2008.1 are
> E[SCF] = -183.689956
> E[CCSD] = -184.208711
> E[CCSD(T)] = -184.235475
> The SCF and CCSD energies agree with a calculation done using
> NWChem; however, NWChem reports the CCSD(T) energy to be
> E[CCSD(T)] = -184.233981

I don't know what is going on here, but my MOLPRO installation gives

  Reference energy                   -183.689955611759
  CCSD Energy                        -184.208710924992
 !CCSD(T) Energy                     -184.233981561579

for the input you supplied, which agrees with the NWChem/literature values you 
cite. Could you run "make test" in the MOLPRO directory? Perhaps the compiler 
or compiler/blas/lapack combination is broken in some way.
Gerald Knizia

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