Self-diffusion and rotational correlation times in liquid acetylene

Abstract

Coefficients of self‐diffusion have been measured in liquid C₂D₂; the data are represented by D = (6.37 ± 1.65) × 10⁻³ exp [− (1.96 ± 0.11)/R T] cm² sec⁻¹. Deuteron spin‐lattice relaxation time data are represented by T₁ = (4.04 ± 0.57) × 10¹ exp [− (1.26 ± 0.08)/R T] sec. The diffusion coefficient data are interpreted by means of a quasilattice model for self‐diffusion which yields a pre‐exponential factor of 5.2 × 10⁻³ cm² sec⁻¹. Rotational correlation times are computed from the T₁ data and interpreted in terms of the quasilattice random flight and the dynamically coherent rotation models for molecular rotation. Both models give reasonably good agreement with experiment.