Molecular description of a planar interface
Continual description . Consider a system in a vessel that has the shape of a rectangular parallelepiped with edges of length l1, l2, l3, directed along the axes of the rectangular coordinate system x, y, z, respectively; the z axis is directed vertically upwards – opposite to the direction of gravity. The volume of the system is V = l1l2l3 and the interface is A = l1l2 (see Fig. 23.1).