Institute of Organic Chemistry
and Biochemistry of the CAS

We employed density functional theory-based ab initio molecular dynamics simulations to examine the hydration structure of several common alkali and alkali earth metal cations. We found that the commonly used atom pairwise dispersion\ncorrection scheme D3, which assigns dispersion coefficients based on the neutral form of the atom rather than its actual oxidation state, leads to inaccuracies in the hydration structures of these cations. We evaluated this effect for lithium, sodium, potassium, andcalcium and found that the inaccuracies are particularly pronounced for sodium and\npotassium compared to the experiment. To remedy this issue, we propose disabling the\nD3 correction specifically for all cation-including pairs, which leads to a much better\nagreement with experimental data.