# Homework Help: Molecular dynamics help - Lennard Jones potention

1. Aug 19, 2014

### Swarby

1. The problem statement, all variables and given/known data

The Lennard-Jones potential function $u(r) = 4ε[(σ/r)^12 - (σ/r)^6]$

If intermolecular interactions are ignored in this calculation for $r > rc$, show that in the mean field approximation in the long range correction [itex] P*LR to the measured pressure is given by:

P*LR / ρ*T* = -16∏ρ*/3T*(r*c)^3 [1- 2/3(rc)^6]

* asterisk denotes MD units

2. Relevant equations

I'm not exactly sure on the equations to be used. I know the Lennard-Jones potential is the starting point, but I need some help beyond this.

3. The attempt at a solution

Unfortunately I don't know where to go from here, if I just have a little nudge I can probably go from there. Many thanks