Dear All,
For my research I'd like to use DFT computation in the ORCA program. I'd like to calculate the changing of bandgap (value calculated from HOMO and LUMO energy) of a molecule depending on the applied pressure. The question is:
Is it possible to set the pressure during geometric optimization using the B3LYP functional? Have any of you ever tried to calculate something like this before?
Thank you for your help!
I think it would not be possible in ORCA, as it does not support periodic calculations. Without PBC the system is just molecule in vacuum, no way to introduce pressure.
You need to use a program that supports PBC calculations (gaussia, VASP, crystal, FHI-AIMS, CP2K, QE, etc.) fortunately there are some that are free or free for academics.
Check out the work by Tim Neudecker
He built exactly what you want. It's called GHOSTSHYP but - as far as I know - only available in Q-Chem. See an example application here Article Can a Finite Chain of Hydrogen Cyanide Molecules Model a Crystal?
If you are interested in a 3D material (not an isolated molecule), than you need to use a periodic code as suggested by Karol Strutyński .
Cheers,
Jan
