Molcas Forum
Support and discussions for Molcas and OpenMolcas users and developers
You are not logged in.
- Topics: Active | Unanswered
Announcement
Please note: The forum's URL has changed. The new URL is: https://molcasforum.univie.ac.at. Please update your bookmarks!
You can choose an avatar and change the default style by going to "Profile" → "Personality" or "Display".Pages: 1
#1 2020-10-10 09:18:21
- David
- Member
- Registered: 2017-05-16
- Posts: 84
CASPT2 and MS-CASPT2
Dear MOLCAS experts, I wonder what is the difference between CASPT2 and MS-CASPT2 optimization in OpenMolCAS?
Is the 'multi' keyword added in the CASPT2 module, that is, MS-CASPT2 optimization?
In addition, can I employ the MS-CASPT2 method for optimization but extract final CASPT2 energies?
This makes me confused, I'd appreciate any help. Thanks in advance.
Offline
#2 2020-10-10 13:33:05
- Ignacio
- Administrator
- From: Uppsala
- Registered: 2015-11-03
- Posts: 1,079
Re: CASPT2 and MS-CASPT2
MS-CASPT2 (not XMS or XDW) is an a posteriori correction to CASPT2 energies, so indeed you can get the SS-CASPT2 energies from a MS-CASPT2 calculation, you just wasted some extra time computing something you don't use.
If with "optimization" you mean geometry optimization, please be more specific. You can do geometry optimization with either SS- or MS-, with numerical gradients in both cases. You can of course compute any kind of energy after the optimization.
Offline
Pages: 1