Evaluation of Quantum Offset in Velocity Imaging-Based Electron Spectrometry

TL;DR

This study investigates the reported quantum offset in velocity imaging-based electron spectrometry, using simulations and experiments, and finds no evidence supporting its existence when proper analysis methods are applied.

Contribution

The paper demonstrates that the previously reported quantum offset is not observed with the MEVELER reconstruction method and proper experimental analysis.

Findings

Simulations show no offset with MEVELER reconstruction.

Experimental measurements of oxygen electron affinity show no offset.

Proper analysis negates the previously claimed quantum offset.

Abstract

Velocity-map imaging of electrons is a pivotal technique in chemical physics. A recent study reported a quantum offset as large as 0.2 cm-1 in velocity imaging-based electron spectrometry [Phys. Rev. Lett. 134, 043001 (2025)]. In this work, we assess the existence this offset through a combination of simulations and experiments. Our simulations reveal that the velocity imaging results reconstructed using the maximum entropy velocity Legendre reconstruction (MEVELER) method exhibit no such offset. Furthermore, experimental measurements of the electron affinity of oxygen conducted at various imaging voltages show no discernible offset attributable to the electric field in the photodetachment region. Therefore, we conclude that there is no evidence for the claimed quantum offset in properly analyzed velocity imaging-based electron spectrometry.