- Radial distribution functions for pure fluids:
- Run
this Applet
for 2-D LJ simulations for a bulk fluid, 25 steps between
display, 50 steps between velocity scale, density of 0.8,
temperature of 1.5, and Number of molecules = 100.
- Pause the simulation after some time and pick one of the
molecules. Count the number of nearest neighbor molecules, and
note the range of distnaces for those.
- Count the number of next nearest neighbors and note the
roughly the ranage of distances occupied by these.
- The radial distribution function describes the probability of
finding a molecule at a distance
*r* from a central molecule
and is normalized such that g(*r*) = 1 for large values
of *r*.
- Plot g(
*r*) for different values of density using
this Applet
for plotting radial distribution functions.
- Choose high and low density, sub- and supercritical
temperatures
- Run this etomic Applet
for the LJ fluid and watch the evolution of g(
*r*) as a
function of time for various densities and temperatures.

- Radial distribution functions for mixtures:
- Run
this Applet
for 2-D LJ simulations for a mixture, density 0.8, temperature
2, 100 molecules, sigma12 = 1, epsilon12 = 2, sigma22 = 1,
epsilon22 = 1, check the random placement box.
- Pause the run after it looks like the system has reached
equilibrium.
- Count the number of blue particles around a green particle and
the number of green particles around a green particle.
- Count the number of blue particles around a blue particle and
the number of green particles around a blue particle.
- Redo this simulation but with epsilon12 = 0.5 instead of
2.
- What differences do you note for the g-g, g-b, b-b, and b-g
nearest neighbors.