Femtosecond electron diffraction: making the "molecular movie"
Bibliographic record
Abstract
The ability to watch atoms move in real time - to directly observe transition states - has been referred to as "making the molecular movie". Femtosecond electron diffraction is ideally suited for this purpose since it records the atomic structure of the sample with sub-Angstrom spatial resolution and femtosecond temporal resolution. Many-body simulations of ultrashort electron pulse propagation dynamics allowed the development of sources for femtosecond electron pulses with sufficient number density to perform near single shot structure determinations, a requirement for studies of irreversible processes. We have obtained atomic level views of melting of thin films of aluminum and gold under strongly driven conditions. The results are consistent with a thermally driven phase transition and the observed time scales reflect the different electron-phonon coupling constants for these metals. Recent technical advances in electron gun design have further improved the temporal resolution of femtosecond electron diffraction. New electron pulse characterization techniques use direct laser-electron interaction and electron-electron interaction to determine the temporal overlap of the pump and probe pulses as well as the time resolution of the system. These advances have made femtosecond electron diffraction capable of observing transition states in molecular systems. The camera for "making the molecular movie" is now in hand.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".