As mentioned earlier, the ability to generate the ground state as one of the response states allows for the study of bond-breaking reactions in the ground state, which has been one of the major limitations of DFT. As a simple test case, the bond breaking of hydrogen fluoride (HF) was investigated using UMRSF-TDDFT. The results, are presented in Fig. where the results of U-SF-TDDFT are also included for comparison.