The SF-TDDFT calculations conducted with the B3LYP and WB97X-D3 functionals yielded 2J values of 80.1 cm -1 and 62.5 cm -1 , respectively, both of which underestimate the experimental value. In contrast, the M06-2X functional provided a value of 135.2 cm -1 , which exceeds the experimental result. This discrepancy in accuracy among the commonly used functionals may stem from the SF-TDDFT method's strong reliance on the proportion of Hartree-Fock (HF) exchange in the functional, with those incorporating 50% HF exchange typically performing best. Consequently, the calculations were repeated using the BHLYP and BHHLYP functionals, both featuring 50% HF exchange. These functionals resulted in the same 2J value of 149.5 cm -1 , offering a better approximation than B3LYP and WB97X-D3, though still not as accurate as M06-2X. However, the SF-TDDFT 2J value of the BHLYP functional shows a huge improvement over its BS-DFT value of 252.68 cm -1 .