Ab initio investigation of structure, spectrum, aromaticity and electronic properties of C 10 carbon cluster

CCSDT(Q)/CBS thermochemistry for the D5h → D10h isomerization in the C10 carbon cluster: Getting the right answer for the right reason

“…12 For this reason, the structure of the cyclic C 10 cluster has attracted considerable attention over the past four decades. 12,13,14,15,16,17,18,19,20,21,22,23 It has long been thought that the cumulenic D 5h (equal bonds, alternating angles) structure is a local minimum and the regular decagon D 10h structure is a first-order saddle point. 15,17 However, the energy difference between the two structures has been a matter of some controversy.…”

Difficulties and Virtues in Assessing the Potential Energy Surfaces of Carbon Clusters via DMBE Theory: Stationary Points of Cκ (κ = 2–10) at the Focal Point

“…This is to be compared with the ab initio value of 5389.9 kJ mol –1 reported by Karton et al and 5373.7 kJ mol –1 predicted from the V (2+3+4) form. So, despite the fact that monocyclic singlet structures were conjectured the most stable forms for the even-numbered C κ [κ = 4­( D 2 h ), 6­( D 3 h ), 8­( C 4 h ), and 10­( D 5 h )] series, ,,,,, the good agreement between the estimated values of W4 for -C κ ( 3 Σ g – ) and the experimental atomization energies is notable.…”

“…Clearly, the elucidation of the structural, spectroscopic, and energetic properties of such species could provide valuable tools for unraveling their underlying chemistry and also for clarifying the unknown growth processes leading to the formation of larger aggregates. Yet, small C κ clusters are highly reactive (short-lived) molecules under most laboratory conditions, which makes their experimental characterization extremely involved. , Moreover, the existence of numerous close-in-energy isomeric forms (ranging from linear chains to monocyclic/polycyclic rings), high-density of low-lying singlet/triplet/quintet electronic states, pronounced biradical character, and (pseudo-) Jahn–Teller effects all complicate their theoretical description. − Definitely, a detailed study of these molecules requires a fruitful interplay of state-of-the-art experimental techniques and high-level ab initio approaches.…”

Swarm Intelligence Steers a Global Minima Search of Clusters Bound on Carbon Nanostructures

“…Thus, a structural analysis of single carbon clusters itself has been an elusive and long-debated topic for theorists. , Monocyclic carbon clusters, popularly known as cyclocarbons, are widely researched in recent times. In 2017, Wang and co-workers studied C 10 using PSO and electronic structure methods . They were able to analyze and predict 30 isomers of C 10 corresponding to various local minima, and the global minimum was found to be a monocyclic ring.…”

“…In 2017, Wang and co-workers studied C 10 using PSO and electronic structure methods. 63 They were able to analyze and predict 30 isomers of C 10 corresponding to various local minima, and the global minimum was found to be a monocyclic ring. When PSO was combined with DFT (M062X/aug-cc-pVTZ and B3LYP/ aug-cc-pVTZ) for energy evaluation and optimization, the global minimum obtained was a polyacetylenic ring of D 5h symmetry, whereas, when PSO was combined with MP2 (augcc-pVDZ) and CCSD (aug-cc-pVDZ) methods, the cumulenic structure was predicted to be the global minimum, and the polyacetylenic structure was one of the local minima.…”