I’d like to use ONIOM to perform a calculation where the system is split into multiple QM methods. For example, I want to make the core of the system rigorous DFT, a next level a simple HF and a 3rd level is just semi-empirical QM.
Looking in the Q-Chem manual, I cannot find a way to do this. Other codes I have observed have this capability (e.g.ORCA, Gaussian, etc.) but I prefer to use Q-Chem due to its ability to use GPUs for the huge systems I am investigation.
How can I accomplish this in Q-Chem?
Thanks for any assistance.