Brillouin scattering in single crystals of γ-oxygen: Determination of the elastic constants at the triple point

Abstract

The technique of high resolution Brillouin spectroscopy has been used to determine the adiabatic elastic constants of oriented single crystals of γ‐oxygen at temperatures near the triple point (54.39 K). The values obtained were c₁₁ = 2.5(98), c₁₂ = 2.0(58), c₄₄ = 0.27(5) (in units of 10¹⁰ dyn cm⁻²) with an estimated absolute uncertainty of ±2%. The resulting value for the elastic anisotropy parameter was found to be 1.0(2). Estimates of the relative values of the elasto‐optic coefficients were also obtained. It is concluded that γ‐oxygen is ’’plastic’’ in nature.