Observation of selective charge separation following strong-field single ionization

In this paper, we report on an apparently anomalous observation in the dissociation channels of singly ionized nitric oxide (NO) molecules. We observe that the NO molecules, when oriented perpendicular to the laser polarization, appear to preferentially dissociate into the N⁺+O channel rather than the N+O⁺ channel, despite the fact that the latter channel is more energetically favorable. A careful examination of the unique electronic structure of the NO molecule suggests that this observation is most likely due to the influence of the detailed electronic structure of NO on its strong-field ionization dynamics, which leads NO⁺ created in strong fields to dissociate differently from that in weak fields. This study reinforces our understanding of the fundamental differences between ionization dynamics in strong fields versus weak fields.