Low-Temperature Kinetics of the HCCN + O <sub>2</sub> Reaction in an Extended Laval Nozzle with Detection by Chirped-Pulse Fourier-Transform Millimeter-Wave Spectroscopy
Bibliographic record
Abstract
We report the first low-temperature kinetics measurements of an HCCN radical–radical reaction. We measured the bimolecular rate coefficients for the HCCN + O 2 reaction under pseudo-first-order conditions inside an extended Laval nozzle with detection by chirped-pulse Fourier-transform millimeter-wave (CP-FT-mmW) spectroscopy. The extended nozzle in which the reaction is performed is followed by a shock-free secondary expansion to low density and low temperature optimal for detection by rotational spectroscopy. We determined the bimolecular rate as (1.67 ± 0.06) × 10 –11 cm 3 molecule –1 s –1 at 20 K and (7.59 ± 0.12) × 10 –12 cm 3 molecule –1 s –1 at 70 K, showing a pronounced negative temperature dependence. The results are discussed in light of recent theoretical calculations and a single previous room-temperature measurement of the reaction rate.
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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 | 0.001 |
| 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".