Hi everyone,

I have a wavefunction that was optimized with G09, with a given functional.

I want to use the checkpoint to read in this WF and just evaluate its energy with a different functional, without any perturbation to the original orbitals.

So far I've tried:

scf=(maxcycle=1) - It doesn't work. That single SCF cycle changes the orbitals.

scf=(maxcycle=0) - It restores the standard number of cycles. So it doesn't work.

guess=(read,only) - It reads the WF and does population analysis, but no energy evaluation.

Any suggestion?

If it's not possible with Gaussian... do you know of any software where this can be done?

Thanks in advance.

Mauricio