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Updated: Jul 31, 2026

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures
Published on: July 2, 2012
Inverted Carbon Geometries: Challenges to Experiment and Theory
Matthias Bremer1,2, Harald Untenecker1, Pavel A Gunchenko3
1⊥Merck KGaA Frankfurter Str. 250, 64293 Darmstadt, Germany.
Abstract:
Disproving a long C-C-bond textbook example: The reported 1.643 Å C-C bond in 5-cyano-1,3-dehydroadamantane was redetermined and "only" amounts to 1.584 Å. While this value is well reproduced with ab initio methods, some common DFT approaches perform poorly and are only consistent with CCSD(T)/cc-pVTZ optimizations for noninverted carbons. Large deviations from experiment were also found for other molecules with atypical electron density distributions, e.g., cubane, bicyclo[2.2.0]hexane, and bicyclo[2.1.0]- and bicyclo[1.1.1]pentane, thereby presenting challenging structures for some DFT implementations.
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