Theoretical assessment of the electro-optical features of the group III nitrides (B12N12, Al12N12 and Ga12N12) and group IV carbides (C24, Si12C12 and Ge12C12) nanoclusters encapsulated with alkali metals (Li, Na and K)

- Encapsulation of Li, Na and K narrow the HOMO-LUMO gaps of the clusters.
- The group III nitrides nanoclusters strongly interacted with the alkali metals.
- First hyperpolarizabilities remarkably enhance for B12N12 encapsulated with Na/K.