Using sequential strong-field double ionization in a pump–probe scheme we show through calculations how electronic dynamics can be prepared and imaged. Electronic dynamics may arise whenever multiple states of the ion are accessed in the ionization step. The dynamics in the cation influence the rate of the second ionization step and the momentum distribution of the ejected electron, allowing their detailed characterization. We show how the probe step is controlled through spatial propensities of the ionizing orbitals and the energy level structure of the dication. Both the final electronic state of the dication and the spin state of the ejected electron pair can be controlled through the time delay between the two ionizing pulses. We discuss how our results will extend to the preparation and measurement of attosecond electron dynamics.Using sequential strong-field double ionization in a pump–probe scheme we show through calculations how electronic dynamics can be prepared and imaged. Electronic dynamics may arise whenever multiple states of the ion are accessed in the ionization step. The dynamics in the cation influence the rate of the second ionization step and the momentum distribution of the ejected electron, allowing their detailed characterization. We show how the probe step is controlled through spatial propensities of the ionizing orbitals and the energy level structure of the dication. Both the final electronic state of the dication and the spin state of the ejected electron pair can be controlled through the time delay between the two ionizing pulses. We discuss how our results will extend to the preparation and measurement of attosecond electron dynamics.

Journal of Physics B Atomic Molecular and Optical PhysicsJan 28, 201139 citations

Direct visualization of the transverse photoemission position within molecules via strong-field photoelectron holography

Jia Min Tan, Qinghua Ke, Dian Wang +5 more

Laser-induced tunneling ionization triggers a broad class of strong-field phenomena in the attosecond community. The understanding and application of these ultrafast phenomena require accurate knowledge of the position information for the tunneling electron wave packet (EWP). Here, with strong-field photoelectron holography, we theoretically demonstrate a scheme to retrieve the position of the EWP emitted from molecules in the direction perpendicular to the tunnel. In our scheme, the photoelectron momentum distributions from strong-field tunneling ionization are obtained by solving the time-dependent Schr\"odinger equation. When the molecule is aligned with a nonzero angle to the linearly polarized laser field, a distinct shift of the holographic pattern in the photoelectron momentum distribution is observed. With the quantum-orbit model, we demonstrate that the shift of the holographic pattern is caused by a nonzero initial transverse position of the EWP immediately after tunneling. By tracing their exact correspondence and examining the shift of the holographic pattern, the transverse emission position of the tunnel-ionized EWP is probed accurately. Furthermore, we demonstrate that the complex Coulomb interaction can be safely canceled in our scheme by performing the scheme for both of the model molecules with the short-range and Coulomb potentials. The validity and accuracy of our scheme are confirmed by its application to different molecules, alignments, and laser parameters.Laser-induced tunneling ionization triggers a broad class of strong-field phenomena in the attosecond community. The understanding and application of these ultrafast phenomena require accurate knowledge of the position information for the tunneling electron wave packet (EWP). Here, with strong-field photoelectron holography, we theoretically demonstrate a scheme to retrieve the position of the EWP emitted from molecules in the direction perpendicular to the tunnel. In our scheme, the photoelectron momentum distributions from strong-field tunneling ionization are obtained by solving the time-dependent Schr\"odinger equation. When the molecule is aligned with a nonzero angle to the linearly polarized laser field, a distinct shift of the holographic pattern in the photoelectron momentum distribution is observed. With the quantum-orbit model, we demonstrate that the shift of the holographic pattern is caused by a nonzero initial transverse position of the EWP immediately after tunneling. By tracing their exact correspondence and examining the shift of the holographic pattern, the transverse emission position of the tunnel-ionized EWP is probed accurately. Furthermore, we demonstrate that the complex Coulomb interaction can be safely canceled in our scheme by performing the scheme for both of the model molecules with the short-range and Coulomb potentials. The validity and accuracy of our scheme are confirmed by its application to different molecules, alignments, and laser parameters.

Physical Review AAug 7, 20234 citations

Nonadiabatic theory for subcycle ionic dynamics in multielectron tunneling ionization

Chi-Hong Yuen

Multielectron tunneling ionization creates ionic coherence crucial for lasing and driving electron motion in molecules. While tunneling is well understood as a single active electron process, less emphasis has been placed on theoretical descriptions of bound electrons during tunneling. This work systematically investigates multielectron tunneling ionization based on the strong field approximation, establishing a theoretical foundation and demonstrating the equivalence of wave function and density matrix approaches for subcycle ionic dynamics. An accurate subcycle nonadiabatic ionization rate is also derived and incorporated into the theory to improve its quantitative accuracy. Applying the theory to N $_{2}$ and CO $_{2}$ , this work showcases how an intense laser field can induce ionic coherence in molecules as observed in previous experiments. These findings encourage future investigations into multielectron tunneling ionization and its applications in lasing and in controlling chemical reactions.Multielectron tunneling ionization creates ionic coherence crucial for lasing and driving electron motion in molecules. While tunneling is well understood as a single active electron process, less emphasis has been placed on theoretical descriptions of bound electrons during tunneling. This work systematically investigates multielectron tunneling ionization based on the strong field approximation, establishing a theoretical foundation and demonstrating the equivalence of wave function and density matrix approaches for subcycle ionic dynamics. An accurate subcycle nonadiabatic ionization rate is also derived and incorporated into the theory to improve its quantitative accuracy. Applying the theory to N$_{2}$ and CO$_{2}$, this work showcases how an intense laser field can induce ionic coherence in molecules as observed in previous experiments. These findings encourage future investigations into multielectron tunneling ionization and its applications in lasing and in controlling chemical reactions.

quant-pharXiv:2601.07050Jan 13, 2026

Quantum-Chemical Approach to Electron Correlations

Peter Fulde

Springer series in solid-state sciencesJan 1, 19930 citations

_{2}

and CO

_{2}

, this work showcases how an intense laser field can induce ionic coherence in molecules as observed in previous experiments. These findings encourage future investigations into multielectron tunneling ionization and its applications in lasing and in controlling chemical reactions.