Molecular Dynamics of the Electron-Induced Reaction of Diiodomethane on Cu(110)
Bibliographic record
Abstract
Diiodomethane is used to generate C 1 fragments at surfaces, en route to higher hydrocarbons. Here scanning tunneling microscopy was employed to examine the interaction of diiodomethane, CH 2 I 2, with a Cu(110) surface, from 4.6 to 8.8 K. In this temperature range unexpectedly rapid thermal reaction resulted in the rupture of two C–I bonds, yielding pairs of I atoms recoiling in opposite directions. Approximately 65% of the carbene, CH 2, product from this highly exothermic (4.1 eV) thermal reaction remained chemisorbed. Two stable physisorbed configurations of diiodomethane were found, “vertical” (75%) and “horizontal” (25%). Electron-induced reaction of these intact adsorbates led to single-electron dissociation of both the C–I bonds, with a minor path leading to single bond breaking to form CH 2 I. Directed recoil of chemisorbed carbene was observed in approximately half the electron-induced reactive events. Simulation of the electron-induced reaction by the impulsive two-state (I2S) model consistently predicted delayed dissociation of the second C–I bond, due to vibrational excitation of the CH 2 I radical product. Theory and experiment agreed in evidencing long-range recoil for the CH 2 along the [11̅0] direction of the copper. This recoiling diradical was shown by the I2S model to undergo migration by a novel process of “walking” along a pair of adjacent copper rows.
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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 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 | 0.000 |
| 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".