There are no other molecules on that side of the wall. So there's an attractive force that makes the velocity within not quite as fast.

墙的另一边没有分子,因此吸引力,会降低球的速度。

麻省理工公开课 - 热力学与动力学课程节选

And then V minus the excluded volume term is equal to RT. Two parameters, this is the attraction between two atoms or molecules in the gas phase.

以及V减去一个排斥项,等于RT，两个参数，这是气体状态下两个原子,或者分子之间的吸引力。

麻省理工公开课 - 热力学与动力学课程节选