Molcas Forum

shuoshuo

Member

From: Beijing Normal University

Registered: 2017-10-18

Posts: 35

[SOLVED] How to specify a mixed basis set in a QM/MM calculation?

Dear molcas experts,

I want to calculate a big molecule in solvent. Considering the computational efficiency, I want to use a mixed basis set. I found there is a method described in the manual to specify basis set to a particular atom.

&GATEWAY
Basis set
C.STO-3G....
C1 0.000000 0.924258 -1.100293 /Angstrom
End of basis
Basis set
C.3-21G....
C2 0.000000 0.000000 -0.519589 /Angstrom
End of basis
Basis set
End of input

But, it doesn't work when running QM/MM calculations.
Is there any way to use a mixed base set in QM/MM calculations ?

Best,
shuo

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: [SOLVED] How to specify a mixed basis set in a QM/MM calculation?

Yes, see http://molcas.gitlab.io/OpenMolcas/sphi … ith-tinker. You should then use the "xyz" input, something like:

&GATEWAY
  Coord = 2

  C   0.000000 0.924258 -1.100293
  C_G 0.000000 0.000000 -0.519589
  Basis = STO-3G,C_G.3-21G
  Expert
  Tinker

shuoshuo

Member

From: Beijing Normal University

Registered: 2017-10-18

Posts: 35

Re: [SOLVED] How to specify a mixed basis set in a QM/MM calculation?

Thanks for your advice. It seems work with new openmolcas, but not old version.

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: [SOLVED] How to specify a mixed basis set in a QM/MM calculation?

Right, this was added in https://gitlab.com/Molcas/OpenMolcas/merge_requests/133