Role of nuclear-electronic coupling in attosecond photoionization of H2

The separation of electronic and nuclear dynamics due to differing timescales is a useful concept for understanding ground-state molecular systems. However, coupling between these degrees of freedom is critical to understanding the evolution of most excited-state systems. We measure two-photon ionization delays of H-2 and compare to calculations of the same measurement in a frozen-nuclei approximation. We find discrepancies between the vibrationally resolved measurement and bond-length-dependent theory, suggesting that nuclear motion affects H-2 photoionization on attosecond timescales. We ascribe our observation to nuclear-electronic channel coupling between continuum vibrational states. Our results demonstrate that nuclear-electronic coupling cannot be neglected in the sudden ionization of molecules containing light atoms.

Automated summary

The study found that nuclear motion affects the photoionization of H-2 on an attosecond timescale, suggesting that nuclear-electronic coupling is crucial in the sudden ionization of molecules containing light atoms.