An ab initio study of water molecules in the bromide ion solvation shell

The solvation shell structure and dynamics of Br- in an aqueous solution of HBr (1.6 M) was studied, under ambient conditions, by ab initio molecular dynamics using the Car-Parrinello approach. The present calculations indicate that Br- is asymmetrically solvated by water. The calculated residence time of water in the inner Br- anion solvation shell agrees well with the most recent experimental estimate. Analysis indicates that the large anion scarcely influences the molecular dipole moment of solvation shell molecules. (C) 2002 American Institute of Physics.