Molecular modeling and investigation of optoelectronic behaviour of metal substituted triamantane

The electronic properties, absorption spectra, and nonlinear optical properties of triamantane substituted with alkali metals were investigated. Upon the substitution of triamantane via alkali metals affect the absorption capacity drastically that also reflect form E-HOMO-E-LUMO (H-L) gap. Compared to triamantane, which has H-L gap of 9.06 eV, the designed molecule 9 has the H-L gap (3.474 eV). Alkali metal substitution at different position in triamantane reviled that specific position is important for enhancing the first order hyperpolarizability (beta(tot)) value. Out of different molecules, 9 has a highest first hyperpolarizability among the designed molecules. Calculated results reviled that the lower crucial transition energy (Delta E = 1.648 eV) is responsible for the significant increase in first hyperpolarizability (beta(tot)). We have also calculated frontier molecular orbitals (FMO), transition density matrix (TDM), and densities of states (DOS) at same level of the theory. The absorption shifts from ultraviolet to visible was observed when triamantane was substituted via alkali metal. It is also observed form spectra that as the size of the alkali metal atoms increases the red shift takes place.