Saitta A Marco, Strässle Thierry, Rousse Gwenaëlle, Hamel Gérard, Klotz Stefan, Nelmes Richard J, Loveday John S
Physique des Milieux Condensés, CNRS-UMR 7602, B77, Université Pierre et Marie Curie, F-75252 Paris, France.
J Chem Phys. 2004 Nov 1;121(17):8430-4. doi: 10.1063/1.1804493.
The structure of amorphous ice under pressure has been studied by molecular dynamics at 160 K. The starting low-density phase undergoes significant changes as the density increases, and at rho=1.51 g/cm(3) our calculated g(OO)(r) is in excellent agreement with in situ neutron diffraction data obtained at 1.8 GPa and 100 K on very high density amorphous ice made at 150 K. As the system is further compressed, in the theoretical simulations, up to rho=1.90 g/cm(3), the structural modifications are continuous up to the highest density. The analysis of orientational distributions reveals that dense amorphous ice is characterized by major distortions of the tetrahedral geometry, and that the pressure structural changes, already observed experimentally at lower densities, can be interpreted as a trend towards a disordered closed-packed structure.
在160K下通过分子动力学研究了受压非晶冰的结构。随着密度增加，起始的低密度相发生显著变化，在ρ = 1.51 g/cm³时，我们计算的g(OO)(r)与在1.8 GPa和100K下对在150K制备的超高密度非晶冰获得的原位中子衍射数据高度吻合。在理论模拟中，随着系统进一步压缩至ρ = 1.90 g/cm³，结构改性一直持续到最高密度。取向分布分析表明，致密非晶冰的特征是四面体几何结构的主要畸变，并且在较低密度下已通过实验观察到的压力结构变化可解释为趋向无序密堆积结构的趋势。
