Phase determination of harmonics by three-color photoionization of aligned molecules: The<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn><mml:none/><mml:none/><mml:mo>+</mml:mo></mml:mmultiscripts></mml:math>system
Bibliographic record
Abstract
We investigate the harmonic phase dependence of photoionization of aligned $\mathrm{H}_{2}{}^{+}$ with three colors: two high-order (uv) harmonics of orders $(q+1)$ and $(q\ensuremath{-}1)$ in the presence of a ``dressing'' ir photon such that the absorption of the $(q\ensuremath{-}1)$ harmonic and one ir photon is resonant with the absorption of the $(q+1)$ harmonic and emission of one ir photon. The transition amplitudes for these two interfering paths are calculated for $\mathrm{H}_{2}{}^{+}$ for a wide range of uv photon energies, internuclear distances $R$, and orientations. The relative phase of the ionizing harmonic photons controls the interference between the paths in the total photoionization amplitude, thus allowing for its measurement. Calculations are obtained using the $\mathrm{H}_{2}{}^{+}$ electron continuum wave functions and Green's functions for two polarizations, parallel $(z)$ and perpendicular $(x)$ to the internuclear axis. It is found that the phase differences of the two transition amplitudes, which are made up of harmonic and molecular phases, exhibit a sharp peak when calculated as a function of harmonic order $q$, and internuclear distance $R$. This occurs for near-vanishing total photoexcitation amplitudes where the phase of the amplitude changes abruptly by $\ensuremath{\pi}$. The orientation dependence of the interfering three-photon photoionization amplitudes provides an additional degree of freedom for harmonic phase measurements using aligned molecules, because of the orientation dependence of the molecular phase inherent in such measurements.
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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) | 0.003 | 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".