title: The aqueous Ca2+ system, in comparison with Zn2+, Fe3+, and Al3+: an ab initio molecular dynamics study.
abstract: Herein, we report on the structure and dynamics of the aqueous Ca(2+) system studied by using ab initio molecular dynamics (AIMD) simulations. Our detailed study revealed the formation of well-formed hydration shells with characteristics that were significantly different to those of bulk water. To facilitate a robust comparison with state-of-the-art X-ray absorption fine structure (XAFS) data, we employ a 1st principles MD-XAFS procedure and directly compare simulated and experimental XAFS spectra. A comparison of the data for the aqueous Ca(2+) system with those of the recently reported Zn(2+), Fe(3+), and Al(3+) species showed that many of their structural characteristics correlated well with charge density on the cation. Some very important exceptions were found, which indicated a strong sensitivity of the solvent structure towards the cation's valence electronic structure. Average dipole moments for the 2nd shell of all cations were suppressed relative to bulk water.
authors: Chemistry and Biochemistry Department, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA. sbogatko@vub.ac.be
authors: Stuart
authors: S
authors: Bogatko
authors: Emilie
authors: E
authors: Cauët
authors: Eric
authors: E
authors: Bylaska
authors: Gregory
authors: G
authors: Schenter
authors: John
authors: J
authors: Fulton
authors: John
authors: J
authors: Weare