Channel coupling in molecular photoemission delays

Photoemission delays are a measurement of the phase distortion of an electronic wavepacket as it escapes a cationic potential during photoionization. Electron-electron and electron-nuclear interactions can couple multiple ionization channels, altering the measured photoionization phase and introducing a delay compared to the expected single channel photoemission time. As a result, photoemission delays are a sensitive probe of dynamic molecular phenomena that can be hard to detect with partial photoionization cross-sections. We study photoionization in both the XUV and X-ray regimes for several molecular targets that display different time dependent potential features, such as fast nuclear motion, shape resonance, and core-ionization. These diverse set of ionization phenomena result in channel coupling that we observe through the photoemission delay.