Structural Evolution and Electronic Properties of Selenium-Doped Boron Clusters SeBn0/− (n = 3–16)

Abstract

A theoretical research of structural evolution, electronic properties, and photoelectron spectra of selenium-doped boron clusters SeBn0/− (n = 3–16) is performed using particle swarm optimization (CALYPSO) software in combination with density functional theory calculations. The lowest energy structures of SeBn0/− (n = 3–16) clusters tend to form quasi-planar or planar structures. Some selenium-doped boron clusters keep a skeleton of the corresponding pure boron clusters; however, the addition of a Se atom modified and improved some of the pure boron cluster structures. In particular, the Se atoms of SeB7−, SeB8−, SeB10−, and SeB12− are connected to the pure quasi-planar B7−, B8−, B10−, and B12− clusters, which leads to planar SeB7−, SeB8−, SeB10−, and SeB12−, respectively. Interestingly, the lowest energy structure of SeB9− is a three-dimensional mushroom-shaped structure, and the SeB9− cluster displays the largest HOMO–LUMO gap of 5.08 eV, which shows the superior chemical stability. Adaptive natural density partitioning (AdNDP) bonding analysis reveals that SeB8 is doubly aromatic, with 6 delocalized π electrons and 6 delocalized σ electrons, whereas SeB9− is doubly antiaromatic, with 4 delocalized π electrons and 12 delocalized σ electrons. Similarly, quasi-planar SeB12 is doubly aromatic, with 6 delocalized π electrons and 14 delocalized σ electrons. The electron localization function (ELF) analysis shows that SeBn0/− (n = 3–16) clusters have different local electron delocalization and whole electron delocalization effects. The simulated photoelectron spectra of SeBn− (n = 3–16) have different characteristic bands that can identify and confirm SeBn− (n = 3–16) combined with future experimental photoelectron spectra. Our research enriches the geometrical structures of small doped boron clusters and can offer insight for boron-based nanomaterials.