Time-dependent fragment emission asymmetry in RABBITT experiments with H₂

Photo-dissociation in a homonuclear diatomic molecule, here H₂, can lead to a preferred direction of the photo-electron emission with respect to the positively charged dissociation fragment, leading to a non-vanishing asymmetry parameter [1].

This process can be understood as a two-electron quantum interferometer with two different dissociation pathways: ground state dissociation (GSD) and bond-softening dissociation (BSD) correlated with gerade and ungerade photoelectron wavefunctions. The acquired phase difference between these two paths determines the emission direction of the electron compared to the proton [2].

In our experiment, the process is driven by an attosecond pulse train (APT) and a phase-locked infrared (IR) field. Here we present an angular resolved coincidence measurement of the photo-electron and the H⁺ and report about electron localization asymmetry that can even be controlled by varying the attosecond time delay between the APT and the IR field.

 

[1] Martin et al. Science 315 629 (2007)

[2] Fischer et al. PRL 110, 213002 (2013)