Planar-to-tubular structural transition in boron clusters: B₂₀ as the embryo of single-walled boron nanotubes

Authors

Boggavarapu Kiran, Washington State University
Satya S. Bulusu, University of Nebraska-LincolnFollow
Hua-Jin Zhai, Washington State University
Soohaeng Yoo, University of Nebraska-Lincoln
Xiao Cheng Zeng, University of Nebraska-LincolnFollow
Lai-Sheng Wang, Washington State UniversityFollow

Date of this Version

1-25-2005

Citation

PNAS, January 25, 2005, vol. 102, no. 4, pp. 961–964.

Comments

U. S. government work.

Abstract

Experimental and computational simulations revealed that boron clusters, which favor planar (2D) structures up to 18 atoms, prefer 3D structures beginning at 20 atoms. Using global optimization methods, we found that the B₂₀ neutral cluster has a double-ring tubular structure with a diameter of 5.2 Å. For the B₂₀^- anion, the tubular structure is shown to be isoenergetic to 2D structures, which were observed and confirmed by photoelectron spectroscopy. The 2D-to-3D structural transition observed at B₂₀, reminiscent of the ring-to-fullerene transition at C₂₀ in carbon clusters, suggests it may be considered as the embryo of the thinnest single-walled boron nanotubes.