Two-photon double ionization with finite pulses: Application of the virtual sequential model to helium

Journal Article · Thu Jul 20 00:00:00 EDT 2023 · Physical Review A

DOI:https://doi.org/10.1103/physreva.108.013114· OSTI ID:1991274

Chattopadhyay, Siddhartha ^[1]; Marante, Carlos ^[2]; Schneider, Barry I. ^[3]; Argenti, Luca ^[2]

---

1. University of Central Florida, Orlando, FL (United States); University of Central Florida
2. University of Central Florida, Orlando, FL (United States)
3. National Institute of Standards and Technology (NIST), Gaithersburg, MD (United States)

As a step toward the full ab initio description of two-photon double ionization processes, we present a finite-pulse version of the virtual-sequential model for polyelectronic atoms. The model relies on the ab initio description of the single ionization scattering states of both the neutral and ionized target system. As a proof of principle and a benchmark, the model is applied to the helium atom using the newstock atomic photoionization code. The results of angularly integrated observables, which are in excellent agreement with existing time-dependent Schrödinger equation (TDSE) simulations, show how the model is able to capture the role of electron correlation in the nonsequential regime, and the influence of autoionizing states in the sequential regime, at a comparatively modest computational cost. The model also reproduces the two-particle interference with ultrashort pulses, which is within reach of current experimental technologies. Furthermore, the model shows the modulation of the joint energy distribution in the vicinity of autoionizing states, which can be probed with extreme-ultraviolet pulses of duration much longer than the characteristic lifetime of the resonance. Furthermore, the formalism discussed here applies also to polyelectronic atoms and molecules, thus opening a window on nonsequential and sequential double ionization in these more complex systems.

• Research Organization: University of Central Florida, Orlando, FL (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020311
• OSTI ID: 1991274
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 1 Vol. 108; ISSN 2469-9926
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
Autoionization & Auger processes
Double photoionization
Electronic excitation & ionization
Multiphoton or tunneling ionization & excitation
Ultrafast phenomena