Anisotropy of Translational Diffusion in Liquid α,ω-Dibromoalkanes

The analysis of the measured temperature dependences of self-diffusion coefficients for prolate ellipsoid type molecules of α,ω-dibromo-methane, -ethane, -octane, -decane and -dodecane performed in the frame of the modified Perrin model enabled to discover anisotropy of translational diffusion in liquids. On the basis of the Eyring theory the effect was confirmed and the jump length of about 7 A for all the molecules was derived. The same jump length for longer molecules was obtained from the Cohen-Turnbull free volume theory.