To get wavefunction and estimate, for instance, HOMO, LUMO, or molecular vibration
there are several way to get wavefunction, But I do not know the differnece
1).
energy, wf = psi4.optimize(level, molecule=molecule, return_wfn=True)
2).
psi4.optimize(level, molecule=molecule)
energy, wf = psi4.energy(level, molecule=molecule, return_wfn=True)
3).
psi4.optimize(level, molecule=molecule)
energy, wf = psi4.frequency(level, molecule, return_wfn)
Each wf are same?
or,
I heve to use 2) to get HOMO LUMO?
I have to use 3) to get molecular vibration information?
Best regards