title: Quantum mechanical/molecular mechanical simulations of the Tl(III) ion in water.
abstract: Classical molecular dynamics (MD) and combined quantum mechanical/molecular mechanical (QM/MM) MD simulations have been performed to investigate the structural and dynamical properties of the Tl(III) ion in water. A six-coordinate hydration structure with a maximum probability of the Tl-O distance at 2.21 A was observed, which is in good agreement with X-ray data. The librational and vibrational spectra of water molecules in the first hydration shell are blue-shifted compared with those of pure liquid water, and the Tl-O stretching force constant was evaluated as 148 Nm(-1). Both structural and dynamical properties show a distortion of the first solvation shell structure. The second shell ligands' mean residence time was determined as 12.8 ps. The Tl(III) ion can be classified as "structure forming" ion; the calculated hydration energy of -986 +/- 9 kcal mol agrees well with the experimental value of -986 kcal mol.
authors.affiliation: Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria.
authors.forename: Viwat
authors.initials: V
authors.lastname: Vchirawongkwin
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hofer
authors.forename: Bernhard R
authors.initials: BR
authors.lastname: Randolf
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Rode