Role of Water Complexes in the Reaction of Propionaldehyde with OH Radicals
Bibliographic record
Abstract
There has been considerable debate and speculation about the role of weakly bound complexes in radical-molecule reactions in the gas phase, especially in atmospheric chemistry. Among the significant number of potentially important molecular aggregates in chemical reactions, water complexes are of particular interest. Beyond the well-known energy transfer role of water in complex-forming reactions, it has been shown that water may also have a catalytic effect on the kinetics of radical-molecule reactions because of reduced reaction barrier heights for the complexes. Here we report studies of the reaction of OH radicals and propionaldehyde in the presence and absence of water vapor between 300 and 60 K in Laval nozzle expansions. Water accelerates the overall reaction at low temperatures but much less pronounced than for the reaction of OH with acetaldehyde reported recently. Quantum chemical calculations help us to understand this behavior, which can be rationalized in terms of the stability of intermediate reaction complexes and the effect of water aggregation on the barrier separating prereactive complexes and products.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".