Molecular Chemistry for Dark Matter III: DarkKROME

Dark matter that is dissipative may cool sufficiently to form compact objects, including black holes. Determining the abundance and mass spectrum of those objects requires an accurate model of the chemistry relevant for the cooling of the dark matter gas. Here we introduce a chemistry tool for dark matter, DarkKROME, an extension of the KROME software package. DarkKROME is designed to include all atomic and molecular processes relevant for dark matter with two unequal-mass fundamental fermions, interacting via a massless-photon mediated $U(1)$ force. We use DarkKROME to perform one-zone collapse simulations and study the evolution of temperature-density phase diagrams for various dark-sector parameters.