Molecular above-threshold-ionization spectra: The effect of moving nuclei
Bibliographic record
Abstract
Exact non-Born-Oppenheimer simulations of a one-dimensional model of one-electron ${\mathrm{H}}_{2}^{+}$ and linear ${\mathrm{H}}_{3}^{2+}$ in an intense short laser pulse are used to investigate the nonlinear multiphoton electron emission spectra, called above threshold ionization (ATI). Due to the rapid proton motion on near-femtosecond time scale, the ATI spectra are found to be produced at the critical internuclear distance ${R}_{c}\ensuremath{\sim}7--8\mathrm{a}.\mathrm{u}.,$ leading to charge-resonance-enhanced ionization (CREI). As a consequence, maxima in the ATI spectra are displaced with respect to the similar H-atom spectra by a laser-induced Stark energy ${E}_{M}{R}_{c}/2,$ where ${E}_{M}$ is the maximum amplitude of the laser field. Highly oscillating ATI spectra occur, which are enhanced by the nuclear motion. These are interpreted as due to coherent excitations of the lowest unoccupied molecular orbitals and highest occupied molecular orbitals, which are also responsible for CREI. Electron rescattering effects in the energy regions of ${10U}_{p}$ and ${8U}_{p},$ where ${U}_{p}$ is the ponderomotive energy, are shown to be substantially reduced due to the rapid molecular dissociation and Coulomb explosion. Nevertheless, the ATI spectra in these energy regions reflect the different electron energies in the rescattering process. Fine structures of the ATI spectra are found to be enhanced by moving nuclei, reflecting the enhancement of resonant transitions by varying Franck-Condon factors during the nuclear motion.
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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".