[molpro-user] {SPAM}? open shell SCF discrepancy with GAUSSIAN09

Jason Byrd byrd at phys.uconn.edu
Thu Jan 21 19:00:59 GMT 2010

Gerald, Kirk,

Thankyou for your help, it indeed was an excited state!


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On 01/21/2010 11:28 AM, Gerald Knizia wrote:
> On Thursday 21 January 2010 16:04, Jason Byrd wrote:
>> I am calculating the structure of KRb2 and came across the following
>> discrepancy.  Using the Def2-TZVPP (testing the following with different
>> basis sets does not change the results) basis set I get the following
>> discrepancy:
>> SCF Done:  E(ROHF) =                  -646.751495036
>> !RHF STATE 1.1 Energy               -646.750268500845
>> Testing this further with GAMESS suggests that the G09 rhf value is
>> correct.  Ive attached the gaussian and molpro output files.
> All three programs are right. There are (at least) two different ROHF
> solutions, and the different programs find different ones (the solutions have
> quite different dipole moments; one might correspond to an excited state).
> You can get the one G09 found in Molpro with
>     {rhf,accu=10,maxit=200,maxdis=8; shift,0,0; occ,15,4}
> or
>     {mcscf;maxit,200;occ,15,4;wf,sym=1,spin=1; orbital,2140.2}
> If you just use "basis=def2-tzvpp" instead of giving the basis and ECP
> manually, there is also the other issue of the core potentials. By default,
> Turbomole associates its basis sets with modified versions of the
> Stuttgart-Koeln-Bonn ECPs, because Turbomole does not support some higher ECP
> projectors. In Molpro, these sets have been linked to the original versions
> of these ECPs. That leads to a tiny additional difference in the energy here:
> def2-TZVPP&  Turbomole's modified ECP28MWB:
>   !RHF STATE 1.1 Energy               -646.751495035794
> def2-TZVPP&  original ECP28MWB:
>   !RHF STATE 1.1 Energy               -646.751496648248
> This is unlikely to cause any real-world trouble, apart from different
> programs giving slightly different answers in absolute energies.

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