Strong Field Molecular Ionization in the Impulsive Limit: Freezing Vibrations with Short Pulses

TL;DR

This paper investigates how pulse duration affects strong-field molecular ionization, revealing a transition from multiple ionic continua to a single dominant continuum with shorter pulses, influenced by vibrational dynamics.

Contribution

It provides experimental and theoretical insights into the role of pulse duration and vibrational motion in determining ionization pathways in molecules.

Findings

Short pulses favor a single ionic continuum.

Longer pulses produce multiple ionic continua.

Vibrational dynamics influence ionization outcomes.

Abstract

We study strong-field molecular ionization as a function of pulse duration. Experimental measurements of the photoelectron yield for a number of molecules reveal competition between different ionization continua (cationic states) which depends strongly on pulse duration. Surprisingly, in the limit of short pulse duration, we find that a single ionic continuum dominates the yield, whereas multiple continua are produced for longer pulses. Using calculations which take vibrational dynamics into account, we interpret our results in terms of nuclear motion and non-adiabatic dynamics during the ionization process.