Communication: Global minimum search of Ag₁₀⁺ with molecular beam optical spectroscopy

The present study is focused on the optical properties of the Ag₁₀⁺ cluster in the photon energy range ℏω = 1.9-4.4 eV. Absorption spectra are recorded by longitudinal molecular beam depletion spectroscopy and compared to optical response calculations using time-dependent density functional theory. Several cluster isomers obtained by the new pool-based parallel implementation of the Birmingham Cluster Genetic Algorithm, coupled with density functional theory, are used in excited state calculations. The experimental observations, together with additional simulations of ion mobilities for the several geometries found within this work using different models, clearly identify the ground state isomer of Ag₁₀⁺ to be composed of two orthogonal interpenetrating pentagonal bipyramids, having overall D(2d) symmetry.