# Tag Info

Let us begin with the following principle: the CC ansatz always returns an appropriate electronic wavefunction (meaning a combination of Slater determinants). Still, at least in a non-relativistic approach, the Hamiltonian does commute with the Spin operator $$S^{2}=S_{+}S_{-}-S_{z}+S_{z}^{2}$$ (I'm using atomic units here) and ...