Elastic Properties of single Crystalline Methane and carbon Bioxide Hydrates

甲烷水合物(MH)是一种类冰化合物，是一种重要的未来能源和温室气体材料。利用原位高压布里渊谱学方法，测定了单晶甲烷水合物在0.6 GPa296K压力下的声速、绝热弹性模数、体积模数、弹性各向异性和柯西破坏随压力的变化规律。而TA模式随压力的轻微软化意味着MH的结构在高压下相对于剪切分量变得不稳定。弹性模数和体积模数表明MH比冰I_h具有更强的可压缩性。这些新的结果对天然气水合物在未来能源中的应用和抑制全球变暖具有重要意义。

Methane hydrate (MH) is an ice-like compound, and becomes an important material with respect to both a substantial future energy resource and a powerful greenhouse gas contributing to the global warming.By using in situ high-pressure Brillouin spectroscopy in a diamond-anvil cell, we have determined the pressure dependence of acoustic velocities, adiabatic elastic moduli, bulk modulus, elastic anisotropy, and Cauchy violation of single-crystal methane hydrate at pressures up to 0.6 Gpa and 296 K.Acoustic velocities show nearly isotropic behaviors with respect to the crystal orientation, and the slight TA-mode softening with pressure implies that the structure of MH is becoming less stable against the shear component under high pressures. Elastic moduli and bulk modulus indicate that MH is slightly more compressible than ice I_h.These new results are important and available to apply gas hydrates (MH) on a future energy resource and to suppress the global warming.