FIG. 20.
(a) and (b) Examples of the difference Cl–I pair distribution functions, ΔgCl–I(r), and the difference C–I pair distribution functions, ΔgC–I(r), obtained from the MD simulation. The blue and red curves are for I–I distance changes from 2.65 Å to 4.0 Å and 2.65 Å to 3.1 Å, respectively. (c) Schematic for the change of the solvation shell due to the elongation of I–I distance. Dotted circles indicate the first solvation shell. The interatomic distance shown in this figure is the distance between the I atom of the solute and the C atom in the solvation shell. Because a CCl4 molecule has one C atom surrounded by four Cl atoms and the Cl atom scatters much more strongly than the C atom, the scattering signal is dominated by the I−Cl contribution. Nevertheless, with the C atom being located at the center of the CCl4 molecule, the I−C distribution provides a more intuitive picture of the size of the solvation shell.