sp-hybridized carbon allotrope molecular structures: An ongoing challenge for density-functional approximations

摘要

The recent synthesis of a C-18 monocyclic ring constitutes a major breakthrough as a new all-carbon disclosed form. However, modern density functional theory approaches do not lead to the correct experimental polyynic structure and favor the cumulenic one instead. We demonstrate here that this serious drawback can be solved by recently developed range-separated nonempirical schemes, independently of which kind of functional is being applied (i.e., semilocal, hybrid, or double-hybrid). Published under license by AIP Publishing.