Photo-Fragmentation of HeH⁺ in a Strong Laser Field

We investigate the photo-dissociation and -ionization of HeH⁺ ions in a strong laser field. In our experiment, a pulsed ultrafast laser beam^‡ intersects a fast (keV) HeH⁺ ion beam target. The fragments, including neutral ones, are measured in coincidence by a position-and-time-sensitive detector. Dissociation and ionization channels and their corresponding pathways will be discussed. Analysis of the H⁺+He dissociation kinetic energy release spectrum provides evidence for photodissociation driven by the permanent dipole moment of the molecule. This finding supports the interpretation of Wustelt et al. [1]. We also observe contributions from the metastable lowest triplet state, which is largely overlooked, in addition to the expected contributions from the singlet ground state.

[1] Wustelt et al., Phys. Rev. Lett. 121, 073203 (2018); ibid 127, 043202 (2021)