Total CSs for the reaction of Si⁺ with H₂S as a function of collision energy E_CM. The black filled diamonds are the experimental data, the blue filled triangles and the red open diamonds are the CSs as estimated from simple capture models, (i.e. Langevin’s and the average dipole orientation model, respectively). The red and green dashed curves are from our fitted model to extract the true CS from the experimental data: the red curve represents the fitting function, obtained by modelling the effective CS, as in Eq. (14); while the green dashed line represents the form of the true CS extracted as a result of the fitting procedure. Further details are discussed in Sect. 4.4.