Molcas Forum

Merlijn M.

Member

Registered: 2017-03-28

Posts: 2

Free energy profiles of diatomic molecules at SO-RASSI LOT.

Hi all,

I was wondering whether it is possible to calculate free energy profiles of diatomic molecules at the RASSI level of theory including spin-orbit coupling?
I read that the mckinley module only works up to the caspt2 level of theory. Is this true and is there a way around it?

Actually, I already calculated the internal energy profile at 0K at this level of theory.
Is there a way to get to the free energy profile using the vibrot module?
I am ultimately interested in the dissociation energy of diatomic molecules containing heavy atoms at finite temperatures (up to 1000K).

Kind regards,

Merlijn Mertens

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,204

Re: Free energy profiles of diatomic molecules at SO-RASSI LOT.

McKinley (and numerical differentiation in general) does not currently support SO-RASSI, because of the need of combining several calculations.

VibRot is totally independent from electronic structure calculations: you perform calculations at different internuclear distances and give the data for the curves to VibRot. But I guess you'll have to work out the free energy from the vibrational and rotational  levels you get.

Merlijn M.

Member

Registered: 2017-03-28

Posts: 2

Re: Free energy profiles of diatomic molecules at SO-RASSI LOT.

Dear Ignacio,

Thank you for this fast answer.
I think I'll manage to work it out!

Kind regards,

Merlijn