External Electric Field Driven Conformations Transition between Lithium Salt and Electride-like Molecule: Intriguing NLO Switches in Li@Corannulene

Abstract

The external electric field has emerged as a powerful tool for building molecular switch with excellent properties. In this work, we investigate that the impact of an external electric field on the transition between lithium salt and electride-like molecule conformations in Li@corannulene. Remarkably, the distance between the Li atom and the corannulene bottom displays a sharp increase under the influence of an external electric field strength of the F-z = 110×10-4 au. As the external electric field increases, the Li atom brings about different directions of charge transfer (CT). The natural population analysis (NPA) charge and the molecular electrostatic potential (ESP) results show that the intermolecular CT occurs from the Li atom to the corannulene with the F-z ranging from 0 to 100×10-4 au. Interestingly, when the external electric field reaches F-z = 110×10-4 au, the CT is oriented from the corannulene to the Li atom. Moreover, the electron localization function (ELF) basins are presented under the F-z = 110×10-4 au, which indicates that Li@corannulene exhibits electride-like (e-...[Li@corannulene]+), and lithiation salt (Li+[corannulene]-) under the F-z = 0 to 100×10-4 au. Significantly, the differences in charge transfer also contribute to a significant improvement in the hyperpolarizabilities (βtot) during the conformations transition from lithiation salt (Li+[corannulene]-) to electride-like (e-...[Li@corannulene]+). This study explores the potential of Li@corannulene as a promising second-order NLO material, and the external electric field provides an efficient strategy for designing and developing NLO switching devices.