Evaluation of quantum offset in velocity imaging-based electron spectrometry

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 [C. Blondel and C. Drag, Phys. Rev. Lett. 134, 043001 (2025)]. In this work, we assess the existence of 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 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.