A fluorescence polarization study of the O<sub>2</sub><sup>+</sup>A<sup>2</sup>Π<sub>u</sub>→ X<sup>2</sup>Π<sub>g</sub>and the b<sup>4</sup>Σ<sub>g</sub><sup>−</sup>→ a<sup>4</sup>Π<sub>u</sub>transitions in the excitation range 17–25 eV
Bibliographic record
Abstract
The fluorescence yields and polarizations of the O2+ A2Πu → X2Πg and the b4Σg− → a4Πu transitions have been measured between their thresholds and 25 eV using synchrotron radiation. The O2+ ions may be formed either through direct photoionization or through excitation into a Rydberg state followed by autoionization. The alignment of the resulting (A2Πu or b4Σg− state) ion has been determined by measuring the degree of linear polarization of the fluorescence emitted in the subsequent decay. The fluorescence yields and polarizations display prominent structure associated with autoionizing Rydberg states belonging to series converging onto the b4Σg−, B2Σg− or the c4Σu− ionization thresholds. The structure in the fluorescence polarization data has enabled the symmetry of the super-excited states to be deduced. Although the interpretation of this symmetry information has been straight-forward in regard to the Rydberg series converging onto the c4Σu− limit, the situation is less clear for the Rydberg series converging onto the b4Σg− or the B2Σg− limits. The measured polarizations have been compared with calculated values and, even for the A2Πu → X2Πg transition where the theoretical model incorporates resonant processes, the agreement is not particularly good.
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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 | 0.000 |
| 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".