Formation and properties of selenium double-helices inside double-wall carbon nanotubes: experiment and theory.

Fujimori, Toshihiko; dos Santos, Renato Batista; Hayashi, Takuya; Endo, Morinobu; Kaneko, Katsumi; Tománek, David · ACS Nano · 2013

basic_science · Level V

Where this comes from

Abstract

We report the production of covalently bonded selenium double-helices within the narrow cavity inside double-wall carbon nanotubes. The double-helix structure, characterized by high-resolution transmission electron microscopy and X-ray diffraction, is completely different from the bulk atomic arrangement and may be considered a new structural phase of Se. Supporting ab initio calculations indicate that the observed encapsulated Se double-helices are radially compressed and have formed from free Se atoms or short chains contained inside carbon nanotubes. The calculated electronic structure of Se double-helices is very different from the bulk system, indicating the possibility to develop a new branch of Se chemistry.