Dynamics of Hydrated <scp>Y³</scp>⁺ Ions in an Aqueous Environment: A Quantum Mechanical Charge Field Molecular Dynamics Simulation Study

ABSTRACT This work presents a quantum mechanical charge field molecular dynamics (QMCF MD) simulation study exploring the structural and dynamic properties of hydrated Y 3+ ions in an aqueous solution. The simulation results reveal the formation of two hydration shells over a simulation time of 180 ps. The first hydration shell predominantly consists of eight water molecules, with a lower probability of nine, indicating a flexible hydration structure. A total of 84 successful ligand exchange events were recorded during the simulation. The mean residence times of the water molecules in the first and second hydration shells were 18.0 and 2.27 ps, respectively. The square antiprism geometry was adopted for the octahydrate, whereas the gyroelongated square antiprism geometry was adopted for the nonahydrate. The vibrational stretching frequency of Y 3+ O bonds was determined to be 352 cm −1 , consistent with the experimental values of 384 and 379 cm −1 of hydrated yttrium perchlorate and yttrium nitrate. These findings indicate that the QMCF MD simulations can effectively describe the hydration structure and dynamics of Y 3+ , providing valuable insights into the behavior of this rare earth ion in aqueous environments and complementing experimental studies of hydrated Y 3+ .