Influence of conformational molecular dynamics on matter wave interferometry

TL;DR

This study shows that internal molecular conformational dynamics significantly influence matter wave interference patterns, enabling structural insights into molecules through quantum interference measurements.

Contribution

It demonstrates for the first time that matter wave interferometry can detect internal conformational changes in molecules, linking quantum phase shifts to molecular structure dynamics.

Findings

Internal molecular dynamics affect quantum phase shifts.

Structural flexibility influences interference patterns.

Quantum interference can reveal molecular conformations.

Abstract

We investigate the influence of thermally activated internal molecular dynamics on the phase shifts of matter waves inside a molecule interferometer. While de Broglie physics generally describes only the center-of-mass motion of a quantum object, our experiment demonstrates that the translational quantum phase is sensitive to dynamic conformational state changes inside the diffracted molecules. The structural flexibility of tailor-made hot organic particles is sufficient to admit a mixture of strongly fluctuating dipole moments. These modify the electric susceptibility and through this the quantum interference pattern in the presence of an external electric field. Detailed molecular dynamics simulations combined with density functional theory allow us to quantify the time-dependent structural reconfigurations and to predict the ensemble-averaged square of the dipole moment which is found to be in good agreement with the interferometric result. The experiment thus opens a new perspective on matter wave interferometry as it demonstrates for the first time that it is possible to collect structural information about molecules even if they are delocalized over more than hundred times their own diameter.