Coherent Intramolecular Excimer Formation in Solid [2,2]‐Paracyclophane: Time‐Resolved Springing of a Molecular “Trap”
Bibliographic record
Abstract
Abstract Impulsive UV excitation unleashes violent wave packet motions in [2,2]‐paracyclophane (2PC) due to relief of ground state inter‐ring repulsion. Contrary to theoretical predictions for the benzene excimer, transient absorption spectroscopy in oriented single crystals and in liquid THF demonstrates that excited 2PC absorbs visible light polarized along all three molecular axes. Absorption polarized perpendicular to the aromatic rings is deeply modulated in time by the ∼0.5 Å of light induced inter‐ring breathing providing changes in potential energy gaps and dipole strengths during coherent intramolecular excimer formation. Overlapping transitions to several higher electronic states and strong non‐Condon effects contribute to the modulating spectra. These insights prove current understanding of the simplest archetypal organic excimer is fundamentally flawed and provide the basis for testing improved electronic structure models. It is hard to overestimate the significance of achieving such improved understanding given the impact of excimers and exciplexes on all aspects of organic molecular photophysics.
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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) | 0.001 | 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 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".