Structure breaking effect of hydrated Cs+

Structural and dynamical properties of the hydrated Cs+ ion have been investigated by performing A initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations at different quantum mechanical levels (HF, B3LYP and BP86). The first shell coordination number was found to be similar to8 in the HF and similar to9 in the B3LYP and BP86 case and several other structural parameters such as angular distribution functions, radial distribution functions, and tilt- and theta-angle distributions allowed to fully characterize the hydration structure of the Cs+ ion. Velocity autocorrelation functions were used to calculate librational and vibrational motions, ion-ligand motions, as well as reorientation times. The strong "structure breaking" effect of Cs+ can be interpreted on the basis of different dynamical parameters such as accelerated water reorientation, mean ligand residence time, and the number of ligand exchange processes.