[en] The first aim of this study was to determine the role of the structurally different kink sites at these steps for the crystal growth kinetics by computing the activation energies of the Ba²⁺, Ra²⁺ and SO₄^2- ion attachment processes. Here, we have combined several advanced methods of computational quantum mechanics to optimize accuracy and efficiency of the simulations: a hybrid Density Functional Theory (DFT) and Soft-sphere Continuum Solvation (SSCS) approach for computation of barite-aqueous phase interface, and a Nudged Elastic Band (NEB) approach for calculation of activation energies. A barite (001) surface structure was constructed, including steps and all relevant attachment positions for kink-site nucleation, and verified by comparison with experimental data. Our simulations show that Ba²⁺ attachment to the [120] steps of the (001) surface is a complicated multistep process, involving several water detachment-steps and the formation of outer, inner sphere and bidentate complexes with the barite surface. Two mechanisms mainly determine the shape of the energy path, the creation of bonds and the dehydration of the attaching ion. Energy differences between ion attachment processes at different sites are predominantly caused by the influence of the different [120] steps. The rate-limiting steps for Ba²⁺ attachment were the formation of the first bond to the barite surface and complete uptake. The Ba²⁺ ion completely attached to the barite surface is the configuration with the lowest energy, and the Ba²⁺ ion completely dissolved is the minimum energy configuration with the highest energy. The energy pathway derived from this study can explain the barite growth exclusively by the driving forces of surface processes, which are also postulated to be responsible for the anisotropic barite (001) surface growth. This is not the case with the classical force-field-based approach of Stack et al. 2012, which shows the same basic minimum energy structures but with different relative energies and the inner sphere complex as the configuration with the lowest energy. The DFT-NEB-SSCS approach also provides more detailed energy paths that allow for an in-depth comparison of the different ion attachment processes at a certain site. On-going simulations for the uptake of ²²⁶Ra into the (001) barite surface indicate distinct differences between Ra²⁺ and Ba²⁺, related to the different water coordination numbers, and slight variations within the attachment path. Ra²⁺ could therefore be kinetically favored during recrystallization due to an easier dehydration compared to Ba²⁺ at the barite (001) surface