Comparison between ab initio and polarizable molecular dynamics simulations of 1-butyl-3-methylimidazolium tetrafluoroborate and chloride in water

Charge transfer and polarisability in ionic liquids: a case study

“…8–12 Ab initio level simulations can also be used in a complementary manner as a benchmark for classical MD simulations. 8,13…”

Computer Simulations of Deep Eutectic Solvents: Challenges, Solutions, and Perspectives

“…There is emerging evidence about the so-called “chloride’s overpolarization” that may be present in polarizable MD simulations. This was first noted by Szabadi et al [ 147 ], who performed aqueous chloride-based ionic liquid simulations, and subsequently reported by de Souza et al [ 140 ] in DES ethaline. This issue has its physical origin in the high polarizability of chloride, Cl = 4.4 Å 3 .…”

“…This can be circumvented by increasing the atomic diameter (𝜎-parameter) of the heavy atom to which, such as a hydrogen, is bound [ 138 , 139 ]. Recently, de Souza et al [ 147 ] showed that using the values of the 𝜎-parameter of the CL&Pol FF leads to an artificial phase separation between the components of the DES ethaline. This can be fixed by carefully adjusting the 𝜎-values of the hydroxyl groups to reproduce ab initio radial distribution functions.…”

“…This issue has its physical origin in the high polarizability of chloride, Cl = 4.4 Å 3 . In the work of Szabadi et al [ 147 ], they noted an artificial alignment of chlorides with water molecules. In turn, de Souza [ 140 ] found that this overpolarization leads to an overestimated spatial nano-heterogeneity, as indicated by peaks and anti-peaks at very low q-vector values in all self- and cross-correlations of the partial X-ray structure factors.…”

“…In turn, de Souza [ 140 ] found that this overpolarization leads to an overestimated spatial nano-heterogeneity, as indicated by peaks and anti-peaks at very low q-vector values in all self- and cross-correlations of the partial X-ray structure factors. Szabadi et al [ 147 ] tried to reduce the chloride’s polarizability, while de Souza et al [ 140 ] extended the application of the Tang–Toennis damping function for chloride’s induced dipole interactions. In both cases, the behavior of the polarizable MD simulations improved.…”