A model for transport of diatomic molecules through elastic solids

Summary The distribution function of diatomic molecules, dissolved in a solid matrix subject to thermal elastic motion, was evaluated in closed form, assuming separability between the translational and rotational degrees of freedom of the solute molecules. The approach was applied to studying the transport of oxygen molecules through atomistic microstructures of atactic poly(vinylchloride) of ca. 40 Å at 318 K. The solubility coefficient was determined from the normalization constant of . The diffusion coefficient was evaluated from the long-term random walks of O₂ molecules on the network of local maxima of . Comparison with experimental data resulted in satisfactory agreement, indicating the viability of the approach.