Nonadiabatic theory for subcycle ionic dynamics in multielectron tunneling ionization

TL;DR

This paper develops a comprehensive nonadiabatic theoretical framework for multielectron tunneling ionization, highlighting ionic coherence effects in molecules under intense laser fields.

Contribution

It establishes a unified wave function and density matrix approach and derives an accurate subcycle nonadiabatic ionization rate for multielectron systems.

Findings

Demonstrates ionic coherence in N₂ and CO₂ under intense laser fields.

Shows equivalence of wave function and density matrix methods for subcycle dynamics.

Provides a more accurate ionization rate incorporating nonadiabatic effects.

Abstract

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.