Optical properties of substances at the critical point

Abstract

Clausius has shown that, assuming the molecules of a substance are spherical perfect conductors, Maxwell’s electromagnetic theory leads to the relation K = 1 + 2 g /1- g , where K is the dielectric constant as defined by Maxwell, and g is the ratio of the volume actually occupied by the molecules to that apparently occupied by the molecules. Therefore g = K - 1/K + 2 = n 2 - 1/ n 2 + 2, since the electromagnetic theory of light requires that the dielectric constant, should be very approximately equal to the square of the refractive index for light of infinite wave-length.