Molecular Dynamics Studies of Concentrated Binary Aqueous Solutions of Lanthanide Salts: Structures and Exchange Dynamics

Abstract

Concentrated binary aqueous solutions of lanthanide (Nd(3+) and Dy(3+)) salts (ClO(4)(-), Cl(-), and NO(3)(-)) have been studied by means of classical molecular dynamics (MD) simulations with explicit polarization and UV-visible spectroscopy. Pair interaction potentials, used for the MD simulations, have been developed in order to reproduce experimental hydration properties. Nd(3+) and Dy(3+) have been chosen because of their position in the lanthanide series: Nd(3+) being a light lanthanide and Dy(3+) a heavy one. They are respectively coordinated to nine and eight water molecules, in pure water, involving changes in their salt hydration structures. Both MD simulations and UV-visible experiments highlight the stronger affinity of nitrate anions toward Ln(3+) compared to perchlorates and chlorides. Dissociation/association processes of Nd(3+)-Cl(-) and Nd(3+)-NO(3)(-) ion pairs in aqueous solution have been analyzed using potential of mean force profile calculations. Furthermore, from MD simulations, it appears that the affinity of anions (perchlorate, chloride, and nitrate) is stronger for Nd(3+) than Dy(3+).

Solute‐Induced Microstructural Transition from Weak Aggregates towards a Curved Film of Surface‐Active Extractants

“…[44] Eu 3 + LJ parameters were determined to reproduce its experimental structural properties in solution, using the Eu 3 + atomic polarizability calculated by ClavaguØra et al [45] The NO 3 À anion was described by the polarizable model defined in a previous study. [34,[46][47][48] These sets of parameters have already provided results in good agreement with experimental data. [46] Atomic partial charges on DMDOHEMA were calculated with the restricted electrostatic potential (RESP) procedure [49] (partial charges on the amide oxygen, ether oxygen and nitrogen atoms of the diamide are respectively : q OA = À0.577, q OE = À0.402 and q N = À0.613).…”

Density functional theory based molecular dynamics study of hydration and electronic properties of aqueous La3+

“…2 where we show La-O and La-H RDF obtained from simulations using both PP1 and PP2. 10,[74][75][76] The role of counterions, at high concentration, on Ln͑III͒ solvation was found to be important and interesting by both theoretical 54,77,78 and experimental sides, 79 pointing out an important role when moving to concentrate solutions. The La-H RDF does not reach zero exactly-even if very small values are reached-since a hydrogen bonding network is established between first and second shell water molecules.…”

Polarizable interaction potential for molecular dynamics simulations of actinoids(III) in liquid water

“…7 The hydration structure and dynamics of Ln 3+ cations is reasonably well established and several experimental and theoretical studies have been devoted to clarify their hydration properties. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Recently, Persson and co-workers 9 reported a thorough extended x-ray absorption fine structure (EXAFS) study on the whole series in liquid water, providing Ln 3+water distances. There is a trend with respect to the coordination number (CN), which changes from 9 to 8 with a continuous shape in the middle of the series.…”