Electronic Hybridization between Closed-Shell Materials

Abstract

Closed-shell structures (noble-gas atoms, nonpolar molecules, and 2D layered materials) gathered together with an equilibrium distance under the balanced forces of van der Waals attraction (London dispersion force) and repulsive electronic interaction (REI). Different terminologies are used in describing the REI in different systems, such as the Pauli repulsion between noble-gas atoms, the repulsive π–π stacking between parallel benzene rings, and the interlayer quasi-bonding (QB) between 2D layered materials such as MoS₂. In the current work, based on density functional theory calculations and explicit accounting for the overlap integral between closed-shell structures in our analysis, we show that the REIs in different systems have the same nature; namely, all can be seen as the QB of the two-orbital–four-electron repulsion interaction or a generalization of it to multiple energy-level interactions. All of the REIs cause asymmetric energy-level splitting and electron-density depletion at the middle region of the quasi-bond due to the occupation of the antibonding state; however, the degree of charge density change and energy-level asymmetry is different. Our consistent understanding deepens the connotation of QB interaction that is widely present in van der Waals materials of different and mixed dimensions, and hence, our insights inspire further studies on the electronic hybridization in these materials and exploring its effects on diverse properties and applications.