English Abstract
Abstract:
The detailed investigation on the alkaline earthides based on 15-crown-5 ether is carried out. These earthides are designed by doping of alkali metal and alkaline earth metal atoms, at the center and outside the complexant, respectively. The interaction energies of the alkaline earthides ranging from − 135.71 kJmol−1 to − 204.76 kJmol−1 demonstrate that these complexes are quite stable thermodynamically. The natural bond orbitals and frontier molecular orbitals’ anatomization shows earthide nature of the designed compounds. Moreover, after doping (alkali and alkaline earth metals) there is clear change seen in the values of certain parameters. HOMO–LUMO gaps decrease, while dipole moment, polarizability and hyperpolarizability increase for doped structures in comparison to bare complexant (15-crown-5 ether). This shows the influence of excess electrons’ presence in the compounds. The excess electron is responsible for the remarkable NLO response of these compounds which is evinced through considerably higher values of hyperpolarizability (the highest hyperpolarizability is equal to 2.5 × 104 au for Li+(15-crown-5)Be−). The controlling factors of hyperpolarizability, ∆µ, fo and ∆E are also examined, and their relationship with hyperpolarizability is studied. To get deep insight into the nonlinear behavior of studied alkaline earthides for experimentalists, frequency-dependent calculations are carried out. The dynamic hyperpolarizability response for electro-optical Pockels’ effect β(− 2ω;ω,0) increases up to 1.5 × 107 au and dynamic hyperpolarizability response in term of SHG increases up to 5.5 × 107 au at dispersion frequency of 1300 nm. Moreover, for further comprehensive analysis of nonlinear optical (NLO) properties, βHRS is also computed. The hyper-Rayleigh scattering hyperpolarizability (βHRS) response is recorded up to 1.8 × 104 au. These remarkable findings will aid in the promotion of the 15-crown-5 ether-based systems for potential uses in efficient nonlinear optical (NLO) materials.
