engleski

The study of the hydration of hydrophobic particles by molecular dynamics simulations

A series of molecular dynamics simulations have been performed in order to evaluate the correlation function between water and various Lennard-Jones particles, ranging in size from 0.2 to 1.5 nm. A second series of simulations has been carried out for a single heptane molecule in water and for a droplet of 19 heptanes in water. The goal was the calculation of the correlation function between the center of mass of the heptane (molecule or droplet) and water. In systems with Lennard-Jones particles, the orientational ordering is determined to be longer in range than the well-known radial ordering. It has been found that the ordering of the dipole angle of water molecules around the smallest particle exhibits behavior different than that observed for other particles. However, the range of all correlation functions is determined to be independent of the size of the solute. Surprisingly, the correlation functions and angle distributions for a single heptane molecule and the heptane droplet were found to be qualitatively the same as for the Lennard-Jones particles of similar size. This indicates that the orientational correlation is principally dependent on the size of the hydrophobic object, while remaining relatively insensitive to its shape.

Molecular Dynamics; Hydrophobic Solvation

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