The hydration properties of Gd(III) and Tb(III): An ab initio quantum mechanical molecular dynamics study

Abstract

The quantum mechanical charge-field molecular dynamics (QMCF-MD) simulation method was employed to study the hydration properties of gadolinium(III) and terbium(III). Slight differences of the solvation shells’ structural and dynamical properties were discovered. While the LnO radial distribution functions are in excellent agreement with recent experiments, average coordination numbers of 8.5 (Gd) and 8.4 (Tb) were found. Vivid ligand exchange dynamics along with rapid intrashell rearrangements were observed, underlined by mean residence times in the picosecond range, which is characteristic for trivalent lanthanoides according to quantum mechanical simulations. Vibrational analysis yielded ion-water force constants below 100Nm−1.