The Temperature Dependence of the Self-Diffusion Coefficients of Argon, Neon, Nitrogen, Oxygen, Carbon Dioxide, and Methane

Abstract

The self-diffusion coefficients of A, Ne, ${\mathrm{N}}_{2}$, ${\mathrm{O}}_{2}$, C${\mathrm{O}}_{2}$, and C${\mathrm{H}}_{4}$ have been measured as functions of the temperature: A, Ne, ${\mathrm{N}}_{2}$, and ${\mathrm{O}}_{2}$ in the range --- 196\ifmmode^\circ\else\textdegree\fi{}C to 80\ifmmode^\circ\else\textdegree\fi{}C, ${\mathrm{CO}}_{2}$ in the range --- 78.5\ifmmode^\circ\else\textdegree\fi{}C to 80\ifmmode^\circ\else\textdegree\fi{}C, and C${\mathrm{H}}_{4}$ in the range --- 183\ifmmode^\circ\else\textdegree\fi{}C to 80\ifmmode^\circ\else\textdegree\fi{}C. The experimental figures have been compared with values calculated on the assumption that the molecular interaction potential is of the form$V(r)=4\ensuremath{\epsilon}[\ensuremath{-}{(\frac{{r}_{0}}{r})}^{6}+{(\frac{{r}_{0}}{r})}^{12}]$ With the exception of the lowest point for methane, all figures are in essential agreement with theory.