Overtone-Induced Reactions on the HO<sub>2</sub>NO<sub>2</sub>Potential Surface
Bibliographic record
Abstract
We report density-functional theory calculations performed at the B3LYP/6-311++G(3df,3pd) level on the lowest energy singlet and triplet potential energy surfaces of the HO 2 NO 2 system. The reaction forming HONO + ground-state oxygen, O 2 ( 3 Σ), from HO 2 + NO 2 proceeds via a triplet transition state which lies about 2 kcal/mol above reagents, and about 22 kcal/mol above ground-state HO 2 NO 2 . Dissociation of ground-state pernitric acid into HO 2 + NO 2 is energetically accessible through excitation of the v = 2 overtone level of the OH stretching vibration (v OH = 2). Overtone excitation into v OH ≥ 3, followed by a singlet−triplet potential surface crossing, could lead to HONO + O 2 ( 3 Σ) products. On the singlet potential surface, the energetic barrier to the reaction forming HONO + O 2 ( 1 Σ) lies very near the product energy. This product channel may be accessible via excitation of the v OH = 3 or 4 overtones. Complexation with a single water molecule does not alter the barrier height to reaction, but may promote reaction by changing the strength and or location of the singlet−triplet coupling. The reaction of HONO (v OH ≥ 3) with O 2 ( 3 Σ) may form HO 2 + NO 2 in polluted urban atmospheres with a rate several orders of magnitude smaller than that of HONO photolysis.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 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".