Radiation Pressure Theory of Thermal Diffusion in Liquids

Abstract

An analysis of the nature of heat in the condensed phases leads to the conclusion that the transport of thermal energy must be accompanied by the development of a "radiation pressure." In line with this conclusion, a force must act on the particles dissolved or suspended in a liquid when a temperature gradient is established in absence of convection. The direction of the force is parallel to the temperature gradient, and its orientation depends on the thermal conductivities and speed of sound both within the liquid and the particles. On this basis a physical explanation of the thermodiffusive phenomena in the condensed phases is advanced.