Several distinct mechanisms of femtosecond laser ablation of thin Ag films from a silica substrate are established in large-scale atomistic simulations and are mapped to the space of film thickness and absorbed fluence. For a fixed film thickness, the increase in fluence results in sequential transitions from melting with no ejection of the film, to film splitting or spallation, to an explosive decomposition of the top part of the film and generation of a residual layer in the lower part of the ablation plume, and to a complete phase decomposition of the film into small droplets and vapor. To facilitate the experimental validation of the computational predictions, the variation of the scattering and reflectivity of the ablation plume is calculated from atomic configurations predicted in the simulations and related to the results of pump-probe optical imaging of the ablation plume.
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