Dynamics of Electron-induced Recoil and Reaction On Single-crystal Copper
Bibliographic record
Abstract
This thesis reports three studies of chemical reactions at the Cu(110) surface at 4.6 K, examined a ‘molecule-at-a-time’ by scanning tunneling microscopy (STM) and density functional theory. The first study reports widely different efficiencies for electron-induced reaction of an aliphatic adsorbate as compared with aromatic. The second describes a novel means of aiming an energized reagent at a fixed vinyl 'target' molecule. In the third an energized reagent is aimed to strike the target at its centre-of-mass, expelling an atom in a new type of reaction we term 'knock-on'. The first study compares electron-induced reaction of pentyl bromide (PeBr) and phenyl bromide (PhBr). A single ~2.0 eV electron induced C–Br bond dissociation for each reagent, with three orders-of-magnitude greater dissociation yield measured for PeBr (2.0 × 10-7 reactive events per electron) than for PhBr (1.7 × 10-10). Lower yield of the aromatic PhBr was attributed to the presence of two additional anionic states, absent for aliphatic PeBr. These additional states provide a pathway for electron transfer to the surface in the case of the aromatic, but not the aliphatic anion. The second study employs a new method permitting the miss-distance (‘impact parameter’) between colliding reagents to be controlled using a highly collimated reactive ‘projectile’ aimed along the surface at a stationary adsorbed ‘target’. Here, a CF2 projectile, recoiling from electron-induced dissociation of chemisorbed CF3, exhibits highly directional travel having
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".