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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".