Fig. illustrates the convergence behavior of Co atom and FeS using B3LYP and DM21. The Co atom converges under B3LYP with strategies A and B, with a smoother convergence observed using B [Fig. ]. For the same atom, DM21's SCF convergence initiated with B3LYP-converged orbitals proceeds smoothly with Strategy A. By contrast, for the FeS molecule, DM21 fails to converge with any of the strategies A, B, or C, as indicated by the erratic energy values with no stabilization even over an extended number of SCF iterations (Fig. ). However, Fig. ) shows that B3LYP encounters no such convergence issues with FeS. to shed light on their different DM21 SCF convergence behaviors.