HYDRATION AND DYNAMICS OF A TETRAMETHYLAMMONIUM ION IN WATER - A COMPUTER-SIMULATION STUDY

Molecular dynamics simulations of one single tetramethylammonium ion i n water have been carried out. The structural analysis revealed the ex istence of a well-defined hydration shell. The orientation and dynamic s of the hydration shell molecules are analyzed. Residence times and h ydration numbers are reported. The dynamical analysis shows that hydra tion shell water molecules have lower self-diffusion coefficients and higher reorientational times than pure water. Translational and reorie ntational motions of the ion are studied. The influence of the assumed water model on the different properties is discussed.