Structure and Dynamics of Au+ Ion in Aqueous Solution: Ab Initio QM/MM MD Simulations

• Published in: Journal of the American Chemical Society Vol. 126; no. 8; pp. 2582 - 2587
• Main Authors: Armunanto, Ria, Schwenk, Christian F, Tran, Hung T, Rode, Bernd M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 03-03-2004
• Subjects: Atomic and molecular physics; Correlation times in molecular dynamics; Exact sciences and technology; Molecular properties and interactions with photons; Physics; Properties of molecules and molecular ions; Hartree-Fock calculations; Aqueous solutions; Solution structure; Radial distribution function; Molecular dynamics method; Theoretical study; Ab initio calculations; Gold ions; Transition elements Ions; Interaction energy
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja037340f

Structure and dynamics of hydrated Au+ have been investigated by means of molecular dynamics simulations based on ab initio quantum mechanical molecular mechanical forces at Hartree−Fock level for the treatment of the first hydration shell. The outer region of the system was described using a newly constructed classical three-body corrected potential. The structure was evaluated in terms of radial and angular distribution functions and coordination number distributions. Water exchange processes between coordination shells and bulk indicate a very labile structure of the first hydration shell whose average coordination number of 4.7 is a mixture of 3-, 4-, 5-, 6-, and 7-coordinated species. Fast water exchange reactions between first and second hydration shell occur, and the second hydration shell is exceptionally large. Therefore, the mean residence time of water molecules in the first hydration shell (5.6 ps/7.5 ps for t* = 0.5 ps/2.0 ps) is shorter than that in the second shell (9.4 ps/21.2 ps for t* = 0.5 ps/2.0 ps), leading to a quite specific picture of a “structure-breaking” effect.