Molecular Dynamics

An alternative approach to studying the behaviour of large systems is simply to solve the equations of motion for a reasonably large number of molecules. Usually this is done by using one of the methods described for Ordinary Differential Equations to solve the coupled equations of motion for the atoms or molecules to be described. Molecular solids in particular can be studied by considering the molecules as rigid objects and using phenomenological classical equations of motion to describe the interaction between them. As a simple example the Lennard-Jones potential

$$\Phi(r) = \epsilon\left(\left(a\over r\right)^{12} - 2\left(a\over r\right)^6\right)$$ (4.19)

has been successfully used to describe the thermodynamics of noble gases.