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The stability of e⁺H^- ₂

Dario Bressanini¹

¹Dipartimento di Scienza e Alta Tecnologia, Università dell'Insubria, Via Valleggio 9, I-22100 Como, Italy.

The Journal of Chemical Physics

|July 9, 2021

Summary

The newly discovered positronic molecule e+H-2 is stable with a single-positron bond. However, it becomes unstable at short distances, decaying into H2 and Ps-.

Area of Science:

Quantum Chemistry
Atomic and Molecular Physics
Positron Interactions

Background:

A novel molecule, e+H-2, featuring a single-positron bond, has been recently discovered.
Understanding the stability of such exotic molecules is crucial for advancing chemical physics.

Purpose of the Study:

To investigate the stability of the e+H-2 molecule.
To determine its global and local stability with respect to various dissociation channels.
To explore potential pathways for its experimental production.

Main Methods:

Utilized quantum Monte Carlo techniques for high-accuracy calculations.
Computed the potential energy curve for the reaction H- + PsH → e+H-2 → H2 + Ps-.

Main Results:

The e+H-2 system exhibits stability against dissociation into H- + PsH, with a binding energy of 23.5(1) mhartree.
The molecule is unstable for internuclear distances R < 3.2 bohrs, decaying into H2 + Ps-.
No other bound structures were identified within this unstable region.

Conclusions:

The single-positron bond in e+H-2 confers stability under certain conditions.
The molecule's instability at short distances suggests specific experimental constraints for its observation.
Further research into production routes is warranted.

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