3.5.1. Oscillator Strength (*f*) Transition Dipole Moment (Debye)

As shown in Table 1, relatively high ' *f* ' values of 0.212 and 0.31 indicate the strong interactions between PA and ChA/DDQ, and therefore, the CT complexes PA-ChA and PA-DDQ have high stability. In addition, the transition dipole moment was recorded as very high (4.82 and 5.62 Debye for PA-ChA and PA-DDQ, respectively), supporting the formation of strong bonded CT complexes between the donor (PA) and acceptors (ChA/DDQ).

**Table 1.** Spectroscopic characteristics of procainamide CT complexes.

