Incorporating Van der waal forces

[hsuya]

Do we have to use DFT-D2 after performing geometry optimization for a particular structure or can we use it later for energy calculation?

[Nordland]

You can choose to use the DFT-D2 forces in geometry or only add it afterwards. I would recommend keeping a consistent model and use DFT-D2 all the way if you want to study the effect of Van der waal forces.

[hsuya]

Okay, thanks