Direct measurements of rate coefficients for the reaction of ethynyl radical (C<sub>2</sub>H) with C<sub>2</sub>H<sub>2</sub> at 90 and 120 K using a pulsed Laval nozzle apparatus
Bibliographic record
Abstract
Rate coefficients for the reaction C 2 H + C 2 H 2 → C 4 H 2 + H are measured at 90 and 120 K by using a new pulsed Laval nozzle apparatus equipped with laser ionization, time‐of‐flight mass spectrometric detection. The C 2 H radicals are generated by 193 nm laser photolysis of C 2 H 2 , and the reaction product, C 4 H 2 , is directly detected by single‐photon ionization at 118 nm (10.5 eV). Rate coefficients of (2.7±0.5) × 10 −10 and (2.5±0.4) × 10 −10 cm 3 molecule −1 s −1 are obtained at 90 and 120 K, compared to the room temperature value of 1.3×10 −10 cm 3 molecule −1 s −1 . The results show a significant negative temperature dependence of the reaction rate coefficient below room temperature. The implications for models of planetary atmospheres, such as for Titan, are discussed.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 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".