In the code, I am finding convergence with mp2 that includes the electron correlation. This might be difficult to converge if there is a lot of interactions and dispersion effects where you might have to fall back to a lower level of theory hartree-fock . The same argument can be made for the basis set. I rope the two in a try and except block as a fallback for the convergence.
try:
psi4.optimize(
'mp2/aug-cc-pvdz',
molecule=universe
)
except:
psi4.optimize(
'hf/6-31g*',
molecule=universe
)
Try not to use STO because it’s known as a not as accurate as you may think in terms of finding the true minimum since it’s orbital sets are low.