Cavity-trapped electrons: lithium doped tetracyano-2,6-naphthoquinodimethane (TNAP) systems

The interesting features in the lithium based electride motived us to explore new species with electride properties. To achieve this goal, the tetracyano-2,6-naphthoquinodimethane (TNAP) species has been used as backbone to investigate systematic addition of lithium atoms to the TNAP backbone (Lin@TNAP (n = 1–4) species) through density functional theory (DFT) simulation. After finding the most stable geometries for each Lin@TNAP (n = 1–4) species by full optimization process, we show their electronic-structural features in this work. In the next step, the properties of electron-density-laplacian (∇2ρ(r)), non-linear-optical (NLO), non-nuclear-attractor (NNA), and electron-localization-function (ELF) have been studied to incorporate the reported Lin@TNAP (n = 1–4) species in two different categories, salt or electride. The obtained outcomes present that the Li1@TNAP and the Li2@TNAP molecules are the lithium-salt. In contrast, the Li3@TNAP and the Li4@TNAP molecules are lithium-based electrides along with the isolated electrons in the molecular structure.