Revisiting the Validation of the KID Methodology through CDFT Descriptors of Fluorescent DNA Staining Dyes

The fulfillment of the ”Koopmans’ theorem in DFT” or KID methodology is verified by means of the calculation of several global descriptors arising from Conceptual DFT. They have been calculated through a
SCF procedure, and by means of the HOMO and LUMO frontier orbitals. The latest Minnesota family of density functionals has been considered and three fluorescent DNA staining dyes have been studied: Hoechst 33258, Hoechst 33342 and Hoechst 34580. On the basis of the obtained Conceptual DFT indices, a series of descriptors have been devised in order to determine the accuracy of each model chemistry considered here in the verification of the mentioned theorem. It is shown that the only density functionals that fulfill this task are those denoted as range-separated hybrids (RSH), while the local density functionals are not useful at all.