Sputtering prefactor from Eq. (1) obtained from the fitting to the data presented in Fig. 2, reported as a function of the sublimation enthalpy of the considered species. A sputtering yield evolving quadratically with the stopping power has been adopted. There is a first-order correlation of with a power law of ΔH_sub fitted and indicated by the dashed line and framed by the dotted lines at 2 σ. We note that for most rare gases, the quadratic behaviour is not constrained by the present data, and only upper limits are therefore obtained.