Convergence of the standard model on the shock thermochemical profiles. Profiles of the kinetic temperature (top panels), the fractional abundances of H and H⁺ (middle panels), and the fractional abundances of He, He⁺, and He⁺⁺ (bottom panels) as functions of the distance in the preshock (left panels) and in the shock (right panels). The black curves show the intermediary profiles computed during the iterative procedure and the colored curves the profiles obtained in the final converged iteration.