For non-charged molecules in non-relativistic conditions (v <<< c) collisions are roughly ruled by what I wrote higher up.
Molecules contain electron clouds, which when the molecules get very, very close, cause temporary polarisation of these molecules, in turn leading to
'sticky' collisions.
Some molecules are permanent dipoles, increasing that 'stickiness'.
But these electrostatic interactions only take place at very close range, because electrostatic repulsions/attractions decrease/increase with the
inverse of the square of the distance (1/r<sup>2</sup> between the
charged particles. |