1. 1 P5-26 Topo·chemical transformations in carbon nanotubes: fracture-induced defect, and ad-dimer welding. S. S. MoliverState University Ulyanovsk, Russia Moliver S. S. (2012)‏ Stone—Wales Defect Generation in Carbon Nanotube Being Fractured. Fullerenes, Nanotubes, and Carbon Nanostructures (2012) 20(4-7), 531-537. Method: Quantum chemical HFR approximation, semi-empirical INDO parametrization, closed- and open-shell population. Model: 1- 2- 3-dimensional super·cell or molecule.

2. 2 Side view Tetragonal bulk-centered super·cell model for topo·chemical transformations in a carbon-tube mesh. D 4h -reduced symmetry: to check for metallic population. Various weld junctions. A lot of endo/exo sites for C n H m free molecules: to build initial SCF approximation in complicated case.

3. 3 Side view Grafted ad-dimer as a part of weld junction between (5,5) tubes. Grafted ad-dimer has other names: (7-5-5-7) di-interstitial, and inverse Stone—Wales. The junction is [2+2] cyclo·addition of r6 bond of the upper tube and grafted ad-dimer of the lower one. Banhart F., Kotakoski J., Krasheninnikov A.V. (2011) «Structural Defects in Graphene.» ACS NANO 5(1), 26-41. Formation energy of grafted ad- dimer in graphene is 5.8 eV.

4. 4 Top view Grafted ad-dimer as a part of weld junction between (5,5) tubes. Sternberg M., et al. (2006) «Carbon Ad-Dimer Defects in Carbon Nanotubes.» Phys. Rev. Lett. 96, 07·55·06. Latham C. D., et al. (2008) «The di-interstitial in graphite.» J. Phys.: Condens. Matter 20, 39·52·20.

5. 5 Top view Grafted ad-dimer as a part of weld junction between (8,0) tubes.

6. 6 Chemical adsorption of acetylene and ad-dimer at (8,0) tube as [2+2] cyclo·addition or di-sigma.

7. 7 Turn view Chemical adsorption of acetylene and ad-dimer at (5,5) tube as [2+2] cyclo·addition. Shulga Y.M., et al. (2009) «Synthesis and properties of C 60 fullerite intercalated by acetylene.» Chem. Phys. Lett. 483, 115-119. High reaction barrier between acetylene adsorption and graft.

8. 8 Dimer's exohedral [2+2] chemisorption on (8,0) tube, and endohedral bonding. Longitudinal (t=0) and transversal (t=1) positions, and graft-like relaxation of the tube (g>0) are taken into account.