Print out virial ratio?

Is there any way to make psi4 print out the value of the virial ratio, especially for a HF or DFT wfn? Or the V and T (potential and kinetic) components of the total energy perhaps? Couldn’t find it in the docs…

We can print virial ratios for CC wavefunctions, oddly enough, but that seems to be it at present.

OK, in that case I would like to request this for an enhancement: to print out the virial ratio and kinetic and potential energy components for all wave functions. Additionally the virial ratio should be written out to the fchk file via the fchk_writer interface, in this format:

Virial Ratio R 2.000693879856458E+00

Would you like to raise the request as an issue on github? Then developers or external contributor don’t lose track of it, and you can also follow any progress there. Otherwise I will open the an issue for you.

If you have programming experience, perhaps you would like to try yourself? There is plenty of guidance from the dev team.

I’m afraid I’m not up to C++ coding, so if you don’t mind creating the github issue, I would appreciate it. Thanks!

no worries, made a post now:

Please follow the issue on github if you can, in case there are question.


This is just a print statement. If this really needs to be done C-side (I’m not sure), that suggests to me we’ll need to move some more things Python-side…

C-side would mostly be exporting some energy terms to a psi4-variable, which could be useful for more purposes. E.g. only the total one-electron energy is available, not the kinetic part.