Density maps provide a three-dimensional representation of density distribution around a central motif. For example, to illustrate the preference of TMA binding to pyridine, we calculated a density map showing 2.3 times the bulk density of carbons of TMA around pyridine (Fig. ). Although density maps cannot be directly validated through experimental measurements, they provide valuable insights the strength and geometric characteristics of cation-π interactions. Moreover, these maps serve as an excellent benchmark for comparison with future ab Initio molecular dynamics (AIMD), underscoring their potential in refining and validating force field models for cation-π interactions.