Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Near-threshold photoelectron spectrum in resonant two-photon ionization of atoms

Andrzej Raczyński, Jarosław Zaremba

Published Nov 1, 1987• 8 citations
Publisher

Abstract

The near-threshold photoelectron spectrum in a resonant two-photon ionization process is investigated using a nonperturbative method. The hydrogen atom is represented by a realistic model including an infinite number of Rydberg states converging at the threshold. When the threshold is crossed a typical two-peak structure of the spectrum is modified by cutting off part of the spectrum which may include one or even two peaks.

DOI
10.1103/physreva.36.5079

Related papers

Two-color above-threshold ionization of atoms

C. S. Han

A nonperturbative method is used to study the two-color multiphoton ionization of atoms by solving the Schr\"odinger equation in momentum space, which facilitates the extraction of the rapidly varying part of the wave function. Our method generalizes the problem for cases where an arbitrary number of ionization photons are absorbed, and also takes into account the threshold shifts due to both the high- and low-frequency fields. The photoelectron energy spectra of the hydrogen atoms are calculated and the dependence on the laser field strengths and frequencies is discussed. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Jun 1, 1996•5 citations

Five-photon ionization of atomic hydrogen at wavelengths around the threshold for four-photon ionization

Yves Gontier, M. Trahin, B. Wolff‐Rottke +3 more

Theoretical and experimental studies show the strong influence of the three-photon nearly resonant 2p state on four- and five-photon ionization of atomic hydrogen near the threshold for four-photon ionization. Changes in five-photon ionization occur when the four-photon ionization channel opens. The angular distributions of photoelectrons from five-photon ionization of H are studied at five wavelengths which cover the range from four-photon resonance with high-lying Rydberg states (n\ensuremath{\ge}10) to direct four-photon ionization into the continuum. The role of resonances in this ionization process is discussed. A fair agreement is found in comparing experimental and theoretical results.

Physical Review A•Nov 1, 1992•3 citations

Two-color multiphoton ionization of atoms

C. S. Han

We present a theoretical study on the two-color multiphoton ionization of atoms using a nonperturbative method of solving the Schr\"odinger equation in momentum space. We generalize the problem for absorption of an arbitrary number of ionization photons and especially focus on the absorption of additional above-threshold high-frequency photons. A systematic calculation on the photoelectron energy spectra for the hydrogen atom is performed.

Physical Review A•May 1, 1997•2 citations

Resonant multiphoton ionization of atomic hydrogen

Yves Gontier, N. K. Rahman, M. Trahin

The resonantly enhanced multiphoton ionization of atomic hydrogen is studied for the case of four-photon ionization (three-photon resonant). The time-dependent probabilities, the shape of the resonance profile at different intensities, and the nonlinear index are computed for coherent light at frequencies around the resonance (365 nm). The systematic dependence of the cross section as a function of the principal quantum number of the resonant state (as this tends towards the Rydberg states) is investigated at zero detuning. The probabilities of absorption of one photon more than necessary for the four-photon ionization process (resonantly enhanced above-threshold ionization) is computed and the relevant branching ratios are examined. Then it is shown that the effect of the spatio-temporal structures of the laser pulse is to red shift the maximum of the resonance profile, whereas that of an ideal chaotic light is to blue shift and broaden the resonance peak. The shape, shift, and width of the profile resulting from both these effects are in very fair agreement with the experimental ones.

Physical Review A•Jun 1, 1988•15 citations

Nonresonant multiphoton ionization in atomic hydrogen

Rajesh Radhakrishnan, R. B. Thayyullathil

The infinite summations over the complete set of unperturbed atomic states appearing in the $N$th-order perturbation theory for multiphoton ionization are performed using the Dalgarno-Lewis method. The relevant transition matrix elements are written in a closed integral form exhibiting all the analytic properties of the amplitude as a function of incident photon energy. The cross sections for two- and three-photon ionization for atomic hydrogen are calculated for both linearly and circularly polarized light with a wide range of photon energy spectrum including the near resonance, and numerical comparison is made with the values obtained by different methods.

Physical Review A•Mar 22, 2004•12 citations

Nonadiabatic transitions between degenerate opposite-parity states of hydrogen in an intense field

Thomas Millack, Bernard Piraux, P. L. Knight

We analyze the photoelectron energy spectrum that results from near-threshold ionization of atomic hydrogen, initially in the 2s state, by a sharply turned on intense field. We demonstrate the existence of resonance structure close to threshold. The structure derives from transitions between degenerate ns and np states; opposite parity, degenerate states in the hydrogen atom are mixed by the nonadiabatic turn-on; at higher energies further structures in the photoelectron energy spectrum are generated through the action of counterrotating terms in the atom-laser coupling. We confirm the existence of a Rydberg series structure and investigate the possibility of q reversals in the line shapes.

Physical Review A•May 1, 1990•6 citations
The near-threshold photoelectron spectrum in a resonant two-photon ionization process is investigated using a nonperturbative method. The hydrogen atom is represented by a realistic model including an infinite number of Rydberg states converging at the threshold. When the threshold is crossed a typical two-peak structure of the spectrum is modified by cutting off part of the spectrum which may include one or even two peaks.
A nonperturbative method is used to study the two-color multiphoton ionization of atoms by solving the Schr\"odinger equation in momentum space, which facilitates the extraction of the rapidly varying part of the wave function. Our method generalizes the problem for cases where an arbitrary number of ionization photons are absorbed, and also takes into account the threshold shifts due to both the high- and low-frequency fields. The photoelectron energy spectra of the hydrogen atoms are calculated and the dependence on the laser field strengths and frequencies is discussed. \textcopyright{} 1996 The American Physical Society.
Theoretical and experimental studies show the strong influence of the three-photon nearly resonant 2p state on four- and five-photon ionization of atomic hydrogen near the threshold for four-photon ionization. Changes in five-photon ionization occur when the four-photon ionization channel opens. The angular distributions of photoelectrons from five-photon ionization of H are studied at five wavelengths which cover the range from four-photon resonance with high-lying Rydberg states (n\ensuremath{\ge}10) to direct four-photon ionization into the continuum. The role of resonances in this ionization process is discussed. A fair agreement is found in comparing experimental and theoretical results.
The resonantly enhanced multiphoton ionization of atomic hydrogen is studied for the case of four-photon ionization (three-photon resonant). The time-dependent probabilities, the shape of the resonance profile at different intensities, and the nonlinear index are computed for coherent light at frequencies around the resonance (365 nm). The systematic dependence of the cross section as a function of the principal quantum number of the resonant state (as this tends towards the Rydberg states) is investigated at zero detuning. The probabilities of absorption of one photon more than necessary for the four-photon ionization process (resonantly enhanced above-threshold ionization) is computed and the relevant branching ratios are examined. Then it is shown that the effect of the spatio-temporal structures of the laser pulse is to red shift the maximum of the resonance profile, whereas that of an ideal chaotic light is to blue shift and broaden the resonance peak. The shape, shift, and width of the profile resulting from both these effects are in very fair agreement with the experimental ones.
The infinite summations over the complete set of unperturbed atomic states appearing in the NNNth-order perturbation theory for multiphoton ionization are performed using the Dalgarno-Lewis method. The relevant transition matrix elements are written in a closed integral form exhibiting all the analytic properties of the amplitude as a function of incident photon energy. The cross sections for two- and three-photon ionization for atomic hydrogen are calculated for both linearly and circularly polarized light with a wide range of photon energy spectrum including the near resonance, and numerical comparison is made with the values obtained by different methods.
We analyze the photoelectron energy spectrum that results from near-threshold ionization of atomic hydrogen, initially in the 2s state, by a sharply turned on intense field. We demonstrate the existence of resonance structure close to threshold. The structure derives from transitions between degenerate ns and np states; opposite parity, degenerate states in the hydrogen atom are mixed by the nonadiabatic turn-on; at higher energies further structures in the photoelectron energy spectrum are generated through the action of counterrotating terms in the atom-laser coupling. We confirm the existence of a Rydberg series structure and investigate the possibility of q reversals in the line shapes.