THERMODYNAMIC DESCRIPTION OF TRANSLATIONAL ENERGY RELAXATION IN BINARY-MIXTURES OF DILUTE GASES

An expression relating the phenomenological coefficient L to the relax ation time tau and temperatures is derived within the formalism of non -equilibrium thermodynamics. For the model of hard spheres the coeffic ient L is expressed by number densities of components, the molecular m asses, the diameters of spheres, the correlation function and temperat ures. The values of tau and L are calculated for binary mixtures of no ble gases. It is shown that L (similarly to tau) is time dependent, be cause the temperatures of components change during the relaxation proc ess. Such changes are smaller than 10 percent even for relatively larg e temperature differences.