Orientational decoherence within molecules and emergence of the molecular shape

TL;DR

This paper explores how electron interactions cause decoherence in molecules, leading to classical-like shapes despite underlying quantum coherence, with numerical evidence from simple molecular systems.

Contribution

It develops a formalism linking electron-induced decoherence to molecular shape emergence and provides numerical results for light-element molecules.

Findings

Electron-nucleus Coulomb interaction induces shape blurring.

Quantum coherences persist in light-element molecules.

Decoherence contributes to classical shape emergence.

Abstract

The question of classicality is addressed in relation with the shape of the nuclear skeleton of molecular systems. As the most natural environment, the electrons of the molecule are considered as continuously monitoring agents for the nuclei. For this picture, an elementary formalism of decoherence theory is developed and numerical results are presented for few-particle systems. The numerical examples suggest that the electron-nucleus Coulomb interaction is sufficient for inducing a blurred shape with strong quantum coherences in compounds of the lightest elements, H$_2$, D$_2$, T$_2$, and HeH$^+$.