Strong-field ionization dynamics of asymmetric equilateral triatomic model molecules in circularly polarized laser fields
Paul M, Gräfe S (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 99
Article Number: 053414
Journal Issue: 5
DOI: 10.1103/PhysRevA.99.053414
Abstract
The strong-field-driven ionization dynamics of larger, nondiatomic molecules still constitutes a major challenge for a theoretical and numerical description. While a full numerical treatment of all electronic and nuclear degrees of freedom is computationally prohibitive, several approaches exist to model photoelectron spectra employing certain approximations. Among them are classical trajectory methods or the so-called strong-field approximation (SFA). Here we investigate in detail the strong-field ionization dynamics of simple, noncollinear triatomic model systems. For a detailed characterization of the ionization process of our system, we combine quantum dynamical simulations, modified classical trajectory calculations, and extensions of the SFA in order to analyze the complex pattern of the photoelectron momentum distribution. We aim at disentangling the contributions of excited states and the long-range character of the potential. We show that upon interaction with circularly polarized laser fields, the long-range character merely induces a small shift in the spectra, while the contribution of excited states is in several cases essential: in particular in near-infrared laser fields, compared to mid-infrared drivers, and for systems with larger internuclear distances, when excited electronic states are energetically closer. Key modifications are for our trajectory model to explicitly incorporate the numerically obtained tunnel barrier width directly into the ionization rate, thereby enabling a spatially anisotropic ionization rate, and an approximate treatment of the contribution of excited states via the Stark shift. In contrast, for the SFA, it is important to include electronically excited states for the description of the initial state. We also discuss the effect of the carrier-envelope phase on the ionization dynamics, as well as the influence of molecular averaging.
Involved external institutions
Germany (DE)How to cite
APA:
Paul, M., & Gräfe, S. (2019). Strong-field ionization dynamics of asymmetric equilateral triatomic model molecules in circularly polarized laser fields. Physical Review A, 99(5). https://doi.org/10.1103/PhysRevA.99.053414
MLA:
Paul, Matthias, and Stefanie Gräfe. "Strong-field ionization dynamics of asymmetric equilateral triatomic model molecules in circularly polarized laser fields." Physical Review A 99.5 (2019).
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