The work required to form unit area of new surface by stretching under equilibrium
conditions. It is numerically equal to the force acting in the
jth direction per unit length of exposed edge, the edge being normal to the
ith direction, that must be applied to a terminating surface to keep it in equilibrium,
the
ith and
jth directions lying in the plane of the surface.
Source:
PAC, 1986, 58, 437
(Interphases in systems of conducting phases (Recommendations 1985))
on page 451
