Enhancing Strong-Field Dissociation of H2+in Helium Nanodroplets

We investigate the above-threshold multiphoton ionization of H2 embedded in superfluid He nanodroplets driven by ultraviolet femtosecond laser pulses. We find that the surrounding He atoms enhance the dissociation of in-droplet HH2 from lower vibrational states as compared to that of isolated gas-phase molecules. As a result, the discrete peaks in the photoelectron energy spectrum correlated with the HHeH from the dissociative in-droplet molecule shift to higher energies. Based on the electron-nuclear correlation, the photoelectrons with higher energies are correlated to the nuclei of the low-vibrationally excited molecular ion as the nuclei share less photon energy. Our time-dependent nuclear wave packet quantum simulation using a simplified He-HH2 system confirms the joint contribution of the driving laser field and the neighboring He atoms to the dissociation dynamics of the solute molecular ion. The results strengthen our understanding of the role of the environment on light-induced ultrafast dynamics of molecules.

Automated summary

We investigated the multiphoton ionization of H2 in superfluid He nanodroplets driven by femtosecond laser pulses and found that the presence of He atoms enhances the dissociation of in-droplet HH2 from lower vibrational states. Consequently, the peaks in the photoelectron energy spectrum shift to higher energies. Our simulation confirms the joint contribution of the laser field and the neighboring He atoms to the dissociation dynamics. These findings improve our understanding of the influence of the environment on light-induced ultrafast dynamics of molecules.