Quantitative (υ, <i>N</i>, <i>K</i><sub>a</sub>) Product State Distributions near the Triplet Threshold for the Reaction H<sub>2</sub>CO → H + HCO Measured by Rydberg Tagging and Laser-Induced Fluorescence
Bibliographic record
Abstract
In this paper, we report quantitative product state distributions for the photolysis of H2CO --> H + HCO in the triplet threshold region, specifically for several rotational states in the 2(2)4(3) and 2(3)4(1) H2CO vibrational states that lie in this region. We have combined the strengths of two complementary techniques, laser-induced fluorescence for fine resolution and H atom Rydberg tagging for the overall distribution, to quantify the upsilon, N, and Ka distributions of the HCO photofragment formed via the singlet and triplet dissociation mechanisms. Both techniques are in quantitative agreement where they overlap and provide calibration or benchmarks that permit extension of the results beyond that possible by each technique on its own. In general agreement with previous studies, broad N and Ka distributions are attributed to reaction on the S0 surface, while narrower distributions are associated with reaction on T1. The broad N and Ka distributions are modeled well by phase space theory. The narrower N and Ka distributions are in good agreement with previous quasi-classical trajectory calculations on the T1 surface. The two techniques are combined to provide quantitative vibrational populations for each initial H2CO vibrational state. For dissociation via the 2(3)4(1) state, the average product vibrational energy (15% of E(avail)) was found to be about half of the rotational energy (30% of E(avail)), independent of the initial H2CO rotational state, irrespective of the singlet or triplet mechanism. For dissociation via the 2(2)4(3) state, the rotational excitation remained about 30% of E(avail), but the vibrational excitation was reduced.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".