Density Functional Study of Functionalization of Carbon Nanotubes with Carbenes
Bibliographic record
Abstract
DFT calculations have been performed on the interactions of carbon nanotubes and carbenes, in order to perform a comparative study of the sidewall functionalization of the two classes of nanotubes, i.e. armchair and zigzag. The systematic investigation of cycloaddition of both zigzag and armchair carbon nanotubes with :CX2 (where X = H, F, Cl, Br, I) has been undertaken. The models selected for zigzag and armchair CNT are (10,0) and (6,6), respectively, since they have comparative radii (~8 A). The bond lengths and binding energies of products are analysed in great detail. The band gaps of these non periodic structures are investigated and correlated with the electronic behavior of 'armchair' and 'zigzag' nanotubes. Our results also confirm the previous studies that armchair nanotubes are thermodynamically more stable than zigzag nanotubes. On comparison of armchair carbon nanotubes with zigzag nanotubes, it is found that trends towards carbenic reactivity are the same in both the cases. The dependence of addition of carbenes on the diameter of the carbon nanotubes is also investigated. The models used for nanotubes in this study range from (3,3) to (10,10). Their reactions with :CH2 have been studied with first principles DFT calculations. An attempt to rationalize the diameter effects is made on the basis of the structures of the nanotubes. It seems that diameter dependence of the reactivity is because of different pyramidalization and π-orbital misalignment angles in different carbon nanotubes. This leads to higher local strain for tubes of smaller diameter that can be partially relaxed by sidewall addition.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".