Figure 3.

Plots of the DFT-computed relative energies of the 26 structures investigated here with respect to graphene as a function of sp–sp² ratios. In the first panel, the two distinct trends are analyzed, while in the second panel, the members of the second trends are collected in different classes, depending on the peculiar topology identified. The seven metallic systems are all in the left panel and grouped in the elongated ellipsoid, while semiconductors with finite band gaps are circled in red. As a term of comparison, the computed energy of the 1D infinite carbyne is reported as an asymptotic limit of the curve (28.41 kcal/mol).