In case of a like-charged ion pair (Na + /Na + and Na -/Na -, respectively), the ions aim at minimizing the electrostatic repulsion, which is reflected by a maximum in the probability distributions at 1 nm. For the oppositely charged Na -/Na + ion pair, the maximum of the distribution is located at about 0.3 nm. Comparing the AdSoS simulations with the FG reference, one observes signif-icant deviations in all cases, which are most pronounced for the positive ion pair. The cutoff is likely to represent a key factor contributing to these deviations, as it affects not only the AdSoS distributions (blue lines in Fig 10), but also causes discrepancies between FG simulations with different cutoffs (green and black lines in Fig. ). The presence of a second ion in the box breaks the spherical symmetry, so that the forces exerted by the environment on each of the ions depend on the direction of their connecting vector. In the case of the FG system, the assumption of a homogeneous dielectric medium outside the cutoff (underlying the reaction-field method) is no longer valid. Therefore, differences arise even for the FG systems with different cutoffs. A similar effect is also in principle possible for the long-range Lennard-Jones interactions. The AdSoS approach also introduces another source of error, which is a dependence of the magnitude of the interactions at (and beyond) the cutoff on the scaling. A finding which supports this hypothesis is the decreasing deviation of the AdSoS distributions relative to the FG reference with increasing cutoff in Fig. . Further investigations will be required to gain a better understanding of the influence of the cutoff in AdSoS, and the development of an adaptive cutoff scheme may be necessary to improve the reliability of AdSoS in an asymmetric setup.