Kinetic measurements on methylidyne radical reactions with several hydrocarbons at low temperatures
Bibliographic record
Abstract
The temperature dependences of the methylidyne radical reactions with methane, allene, methylacetylene and propene were studied. This work was carried out in a supersonic flow reactor coupled with pulsed laser photolysis (PLP) and laser-induced fluorescence (LIF) techniques. Three Laval nozzles were designed to provide uniform supersonic expansions of nitrogen at Mach 2 and of argon at Mach 2 and 3 to reach low temperatures, e.g. 170, 128 and 77 K, respectively. CH radicals were produced by PLP of CHBr3 at 266 nm and probed by LIF. The exponential decays of the CH fluorescence were acquired, hydrocarbons being introduced in excess. The rate constants for the CH+CH4 reaction are in good agreement with the temperature dependence proposed by Canosa et al. (A. Canosa, I. R. Sims, D. Travers, I. W. M. Smith and B. R. Rowe, Astron. Astrophys., 1997, 323, 644-651, ) i.e. 3.96x10(-8)(T/K)(-1.04) exp(-36.1 K/T) in the range 23-298 K. The rate constants of the CH+C3H4(allene), CH+C3H4(methylacetylene) and CH+C3H6(propene) reactions exhibit a small temperature dependence between 77 and 170 K, with a maximum rate around 100 K close to (4.3-4.6)x10(-10) cm3 molecule-1 s-1.
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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 | 0.000 |
| 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) | 0.001 | 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".