Molcas Forum

lijingbai2009

Member

Registered: 2019-08-28

Posts: 29

CI derivatives after ESPF in QMMM calculation

Dear developer,

I have a question regarding the CI derivatives in the QMMM calculation. Molcas prints out the CI derivatives, CSF derivatives, and total derivatives. The QMMM part prints a "molecular gradients after ESPF" section, but which derivatives do they correspond to?

Thanks,
Jingbai

niko

Member

From: Marseille

Registered: 2015-11-08

Posts: 59

Website

Re: CI derivatives after ESPF in QMMM calculation

Hi, the general message "molecular gradients after ESPF" indicates that the total energy gradient wrt nuclear coordinates has been updated with QM/MM contributions.
Hope this helps.

lijingbai2009

Member

Registered: 2019-08-28

Posts: 29

Re: CI derivatives after ESPF in QMMM calculation

Hi niko,

Thanks for replying. I understand that the total energy gradient has been updated with QM/MM. What I am asking is the CI derivative in a NAC calculation with QM/MM, although it still prints the same title as energy gradient. In a gas phase NAC calculation, I obtain three tables, CI derivatives, CSF derivatives, and total derivatives. And the total coupling = CI derivatives/energy gap + CSF derivatives. But in a QM/MM calculation, I only obtain one table which has been updated with QM/MM contributions. I am not sure what exactly these couplings are.

I hope this makes my question clearer.
Thanks,
Jingbai