Single-Crystal Elasticity of α-Hydroquinone-An Analogue for Organic Planetary Materials.

Abstract

In this study, we measured the single-crystal elasticity of α-hydroquinone at ambient conditions using Brillouin spectroscopy to assess the feasibility of this technique for studying the mechanical properties of organic ices in the outer solar system. In this study, α-hydroquinone serves as an ambient temperature analogue for low-temperature organic ices on Titan and other solar system bodies. We found that a satisfactory Brillouin spectrum can be obtained in less than 5 min of experimental time with negligible damage to the sample. The best fit single-crystal elastic moduli of α-hydroquinone were determined as C ₁₁ = 13.67(8) GPa, C ₃₃ = 10.08(6) GPa, C ₄₄ = 4.54(5) GPa, C ₁₂ = 6.9(7) GPa, C ₁₃ = 7.02(7) GPa, C ₁₄ = 0.54(4) GPa, C ₂₅ = 0.51(9) GPa, and C ₆₆ = (C ₁₁ - C ₁₂)/2 = 3.4(3) GPa, with bulk modulus K _S = 8.7(2) GPa and shear modulus G = 3.4(3) GPa. These results demonstrate that Brillouin spectroscopy is a powerful tool for characterizing the elastic properties of organic materials. The elastic properties of organic ices can be broadly applied to understand planetary surface processes and also aid in evaluating the feasibility and technical readiness of future lander, sampling, and rover missions in the outer solar system.