State-selective photodissociation dynamics of formaldehyde: Near threshold studies of the H+HCO product channel
Bibliographic record
Abstract
The laser-induced photodissociation of formaldehyde in the wavelength range 309<lambda<330 nm has been investigated using H (Rydberg) atom photofragment translational spectroscopy. Photolysis wavelengths corresponding to specific rovibronic transitions in the A (1)A2<--X (1)A1 2(0)(1)4(0)(3), 2(0)(2)4(0)(1), 2(0)(2)4(0)(3), 2(0)(3)4(0)(1), and 2(0)(1)5(0)(1) bands of H(2)CO were studied. The total kinetic energy release spectra so derived can be used to determine partial rotational state population distributions of the HCO cofragment. HCO product state distributions have been derived following the population of various different N(Ka) levels in the A (1)A2 2(2)4(3) and 2(3)4(1) states. Two distinct spectral signatures are identified, suggesting competition between dissociation pathways involving the X (1)A1 and the a (3)A2 potential energy surfaces. Most rovibrational states of H(2)CO(A 1A(2)) investigated in this work produceH+HCO(X (2)A') photofragments with a broad kinetic energy distribution and significant population in high energy rotational states of HCO. Photodissociation via the A (1)A2 2(2)4(3) 1(1,1) (and 1(1,0)) rovibronic states yields predominantly HCO fragments with low internal energy, a signature that these rovibronic levels are perturbed by the a (3)A2 state. The results also suggest the need for further careful measurements of the H+HCO quantum yield from H(2)CO photolysis at energies approaching, and above, the barrier to C-H bond fission on the a (3)A2 potential energy surface.
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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 | 0.000 |
| 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".