Strong-field dissociative ionization of a linear triatomic molecule: Relationship between Coulomb-explosion energies and bond angle

Correlation images of the symmetric six-electron Coulomb-explosion channel of CO₂ were used to isolate specific geometries (linear and bent) for angular-resolved analysis of the Coulomb-explosion energy in the framework of both the critical radius Rc and dynamic screening models. We show that it is possible to connect the Rc and screening pictures through a single parameter, a charge defect σ, which depends on the charge state and the ratio between Rc and the equilibrium bond length. Our data show that Rc and hence σ are slow varying functions of bond angle between 145^∘ and 180^∘ with Rc~4a.u. and σ~0.5 for the symmetric six-electron channel of CO₂. In the Rc picture, the experimental value for Rc is consistent with a theoretical value associated with CO₂³⁺, which is considerably smaller than that associated with CO₂⁺(~6a.u.).