Interference effects due to nuclear motion of the hydrogen molecule

TL;DR

This paper demonstrates how two-particle interference patterns can be used to probe nuclear motion in hydrogen molecules, revealing rotational states through phase-shifts in atomic fragment detection.

Contribution

It introduces a method to detect molecular rotation via quantum interference of dissociation fragments, highlighting the role of two-particle correlations.

Findings

Interference patterns encode information about molecular rotational states.

Phase-shifts in fragment detection reveal nuclear motion signatures.

Method applicable under realistic experimental conditions.

Abstract

We show that two-particle interferences can be used to probe the nuclear motion in a doubly-excited hydrogen molecule. The dissociation of molecular hydrogen by electron impact involves several decay channels, associated to different molecular rotational states, which produce quantum interferences in the detection of the atomic fragments. Thanks to the correlations between the angular momentum and vibrational states of the molecule, the fragments arising from each dissociation channel carry out a phase-shift which is a signature of the molecule rotation. These phase-shifts, which cannot be observed in a single-atom detection scheme, may be witnessed in realistic experimental conditions in a time-of-flight coincidence measurement. We analyse the interferences arising from the two lowest-energy rotational states of a para-hydrogen molecule. Our result shows the relevance of two-fragments correlations to track the molecular rotation.