Instead of a multiconfigurational wave function in CASSCF or CASCI, the brokensymmetry (BS) DFT is also a popular and well-established approach to tackle the openshell states, and the approach is feasible even for relatively large systems. However, the accuracy of BS-DFT depends on the exchange-correlation functional being used. In order to evaluate the reliability of different functionals, we will compare the results obtained from BS-DFT with our references for J and ΔEspin (see computational details).