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Title: B{sub 27}{sup −}: Appearance of the smallest planar boron cluster containing a hexagonal vacancy

Photoelectron spectroscopy and ab initio calculations have been carried out to probe the structures and chemical bonding of the B{sub 27}{sup −} cluster. Comparison between the experimental spectrum and the theoretical results reveals a two-dimensional (2D) global minimum with a triangular lattice containing a tetragonal defect (I) and two low-lying 2D isomers (II and III), each with a hexagonal vacancy. All three 2D isomers have 16 peripheral boron atoms and 11 inner boron atoms. Isomer I is shown to be mainly responsible for the observed photoelectron spectrum with isomers II and III as minor contributors. Chemical bonding analyses of these three isomers show that they all feature 16 localized peripheral B–B σ-bonds. Additionally, isomer I possesses 16 delocalized σ bonds and nine delocalized π bonds, while isomers II and III each contain 17 delocalized σ bonds and eight delocalized π bonds. It is found that the hexagonal vacancy is associated generally with an increase of delocalized σ bonds at the expense of delocalized π bonds in 2D boron clusters. The hexagonal vacancy, characteristic of borophenes, is found to be a general structural feature for mid-sized boron clusters. The current study shows that B{sub 27}{sup −} is the first boron cluster,more » where a hexagonal vacancy appears among the low-lying isomers accessible experimentally.« less
Authors:
; ;  [1] ; ;  [2]
  1. Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)
  2. Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)
Publication Date:
OSTI Identifier:
22415870
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMIC CLUSTERS; ATOMS; BORON; CHEMICAL BONDS; COMPARATIVE EVALUATIONS; ELECTRON SPECTRA; ISOMERS; PHOTOELECTRON SPECTROSCOPY; PROBES; TWO-DIMENSIONAL SYSTEMS; VACANCIES