Theoretical study of electronic structure and third-order optical properties of beryllium-hydrocarbon complexes

► Be metal forms fairly stable complexes with unsaturated hydrocarbons. ► The cubic polarizability of hydrocarbons enhances appreciably on complexation with Be. ► Two-photon contributions of second-hyperpolarizability of the complexes are significant. ► Chosen Be-complexes are mostly optically transparent in the visible region. ► The second-hyperpolarizability bears nice correlation with linear polarizability.