Excitation-energy dependence of transient grating spectroscopy in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>-carotene
Bibliographic record
Abstract
Transient grating (TG) signals from $\ensuremath{\beta}$-carotene were measured at various excitation energies (wavelengths). Clear coherent oscillations with a period of a few tens of femtoseconds were observed when the excitation energy was tuned in the vicinity of the absorption edge. It was found that the TG signal is very sensitive to the excitation energy. When the TG signal is measured near the absorption maximum, following the coherent spike at the origin of the time axis, weak coherent oscillations are observed superimposed on a slowly varying background. The rise time of this slowly varying background is 0.4 ps and is followed by the slow decay with a 5 ps time constant. As the excitation energy is decreased the coherent oscillations become more prominent. The coherent oscillations and the slowly varying background become very weak again when the excitation energy is lower than the absorption edge. The TG signals were calculated using two sets of energy and Feynman diagrams to investigate possible pathways of the electronic internal conversion and vibronic decoherence processes. The modeling indicates that the vibronic coherence, initially established by pumping into the excited state ${\text{S}}_{2}$, instantaneously decays due to relaxation into an intermediate state ${\text{S}}_{\text{x}}$, which is located between ${\text{S}}_{2}$ and ${\text{S}}_{1}$. Possible interpretation of the nature of the ${\text{S}}_{\text{x}}$ state is discussed.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".