Theoretical study of benzene, toluene, and dibromobenzene at a Si(111)7×7 surface
Bibliographic record
Abstract
Abstract Theoretical Austin model 1 (AM1) calculations on the adsorption of benzene and toluene on Si(111)7×7 are presented. Both physisorbed and chemi‐sorbed states have been calculated for up to three adsorbed molecules per half unit cell of the Si(111)7×7 surface. Secondly, theoretical calculations on the induced attachment of benzene as well as rationalization of the dynamics of the halogenation reaction of 1,2‐ and 1,4‐dibromobenzene on Si(111)7×7 are reviewed. The main incentive for this study was the interpretation of recent experimental scanning tunneling microscopy (STM) results from the Toronto laboratory on a new electron‐induced or photo‐induced attachment process for benzene on Si(111), and, particularly, experimental results related to the thermal dissociative reactions of 1,2‐ and 1,4‐dibromobenzene on a Si(111)7×7 surface. The central objective is to relate the reagent geometry in 1,2‐dibromobenzene and 1,4‐dibromobenzene to the Br‐Br pair distance of dibrominated Si(111)7×7. For benzene, we propose a possible path for the conversion from the normal strained di‐sigma‐bound state (S) at Si(111) to a more strongly bound state (B) consisting of a phenyl plus an H‐atom adsorbed species. For 1,2‐ and 1,4‐dibromobenzene dibromination of silicon, evidence has been found for two mechanisms of reaction. One reaction pathway involves intermediate binding of the organic molecule on the Si surface through C‐Si bonds, analogous to the benzene S structure. The second dynamical pathway involves intermediate binding through weak Br. Si attachment followed by formation of pairs of covalently‐bound Br‐Si. The outcomes from the two dynamical pathways are consistent with the observed STM patterns for pairs of Br‐Si at Si(111) 7×7 due to the reaction of 1,2‐ and 1,4‐dibromobenzene.
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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 | 0.000 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".