Molecular Orbital Imaging of the Acetone S-2 Excited State Using Time-Resolved (e, 2e) Electron Momentum Spectroscopy

Abstract

We report a time-resolved (e, 2e) experiment on the deuterated acetone molecule in the S-2 Rydberg state with a lifetime of 13.5 ps. The acetone S-2 state was prepared by a 195 nm pump laser and probed with electron momentum spectroscopy using a 1.2 keV incident electron beam of 1 ps temporal width. In spite of the low data statistics as well as of the limited time resolution (+/- 35 ps) due to velocity mismatch, the experimental results clearly demonstrate that electron momentum spectroscopy measurements of short-lived transient species are feasible, opening the door to time-resolved orbital imaging in momentum space.