Consequently, the projected DOS demonstrates that structural distortions lead to the formation of intermediate levels within the bandgap of these materials. To better illustrate the differences observed in the emission spectra of both Zn6O6 and Zn6S6 clusters in terms of the order-disorder , where NBOES and NBOGS are the natural charges of the excited and ground-state of these clusters, respectively. Hence, the estimated μCT value for the Zn6O6 cluster is 0.12672 e, which is much smaller than that obtained for the Zn6S6 cluster (0.40174 e). These μCT values are in alignment with the general tendency observed in other electronic properties, as the intense emission of Zn6S6 cluster is reflected by higher charge transfer between donor and acceptor NBOs. The difference between the lowest excited singlet (S1) state and triplet (T1) state energy gap (ΔES-T) values were 0.90 eV for Zn6O6 and 1.13 eV