AbstractThis article shows that with our Hylleras‐functional based method1 for generating correlation orbitals, we can determine electronic structures for small polyatomic systems very accurately. The procedure is ab initio, uses conventional Gaussian basis sets, and solves the electronic Schrödinger equation with the coupled cluster method. A comparison is made with MRCI results obtained in equivalent basis sets for the HF, H2O, and NH3 molecules.