Does anyone know of a simple, existing way to get the Coulomb and Exchange energy components to the HF energy?

# Exchange and Coulomb components in HF energy

**jmisiewicz**#2

It looks like the Coulomb and Exchange energies are added together almost instantly upon computation. You’d either have to modify the `compute_E`

functions in `libscf_solver`

to store those contributions to variables or get the electron repulsion integral tensor and the orbital coefficients and manually compute the Coulomb and exchange components, Psi4Numpy style.

**Rollin_King**#4

Thanks to both of you. It’s peculiar that our output file contains the “exchange gradient” but no one seems to have ever wanted to know the exchange energy. Of course I was wondering if this data was already printed or stored somewhere. I will implement something like you suggest. Thanks again.

**dgasmith**#5

I don’t see an “exchange gradient”, you might be referring to the exchange contributed to the nuclear gradient?

**Rollin_King**#8

My mistake then. I haven’t thought through the gradient contributions in awhile. But, yes, it’s the energy I’m interested in.

**jmisiewicz**#9

For organizational purposes, I marked this question as solved. If it isn’t solved, let me know, and I can undo it.

**system**closed #10

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