Theory of multiphoton single and double ionization of two-electron atomic systems driven by short-wavelength electric fields: An<i>ab initio</i>treatment
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Bibliographic record
Abstract
We give a detailed account of an ab initio computational treatment of multiphoton single ionization (with or without excitation) as well as double ionization of two-electron atoms exposed to short-wavelength electric fields. This treatment is time dependent and based on a spectral method of configuration interaction type combined with Jacobi or $J$-matrix calculations. It involves a complete treatment of electron-electron correlation in the initial and final states as well as during the time propagation. The atom eigenvalue problem is first solved by means of the spectral method. It consists of expanding the atom wave function in a basis of products of complex Coulomb-Sturmian functions of the electron radial coordinates and bipolar harmonics of the angular coordinates. This method allows a high-resolution study of many atomic states, in particular high-lying singly excited states as well as many doubly excited states. Results for He are presented and discussed in detail. The time-dependent Schr\"odinger equation is then solved by means of an explicit scheme of Runge-Kutta type. An accurate calculation of the probability of single and double ionization is carried out by projecting the ionizing wave packet on fully correlated multichannel scattering wave functions generated by means of the $J$-matrix method. After a detailed analysis of the accuracy of this method, we show that our results for the total cross section of one-photon single and double ionization of He and ${\mathrm{H}}^{\ensuremath{-}}$ are in very good agreement with those obtained by the most sophisticated approaches. Two-photon double ionization of He is then considered, and results are presented in a frequency regime where substantial discrepancies subsist between all existing calculations. Our results demonstrate that electron correlations in the final state play a significant role.
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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 it