How to compute the SCF unrelaxed energy?

Psi4Education
1

Here is my code snippet computing the relaxed energy to compute the dipole moment and polarizability using the pyhton interface:

    psi4.set_options({
        'perturb_h': True,
        'perturb_with': 'dipole',
        'perturb_dipole':h.tolist(), # h is a np array of size 3 containing the field strength
    })
    E_perturbed = psi4.energy('scf') #- mol.nuclear_repulsion_energy()
    return E_perturbed

How can I compute the unrelaxed energies for the same purpose?

2

I don’t understand what an “unrelaxed energy” is in this context.

Normally, the distinction between “relaxed” and “unrelaxed” properties (and I’m assuming you want to calculate these by finite difference of energies) is only meaningful for electronic structure methods that do not variationally optimize the orbitals.