We investigate the effect of cylindrical nano-confinement on the phase behaviour of a rigid model of carbon dioxide using both molecular dynamics and well tempered metadynamics. To this aim we study a simplified pore model across a parameter space comprising pore diameter, CO₂-pore wall potential and CO₂ density. In order to systematically identify ordering events within the pore model we devise a generally applicable approach based on the analysis of the distribution of intermolecular orientations. Our simulations suggest that, while confinement in nano-pores inhibits the formation of known crystal structures, it induces a remarkable variety of ordered packings unrelated to their bulk counterparts, and favours the establishment of short range order in the fluid phase. We summarise our findings by proposing a qualitative phase diagram for this model.

中文翻译：

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局限在圆柱形纳米孔中的 CO ₂填充多态性†

我们使用分子动力学和良好的变质动力学研究了圆柱形纳米约束对二氧化碳刚性模型相行为的影响。为此，我们研究了包括孔隙直径，CO ₂孔壁势和CO ₂在内的参数空间的简化孔隙模型。密度。为了系统地确定孔隙模型中的有序事件，我们基于分子间取向分布的分析设计了一种普遍适用的方法。我们的模拟表明，虽然限制在纳米孔中会抑制已知晶体结构的形成，但它会诱导大量与其有序的堆积物无关的有序堆积，并有利于在液相中建立短程有序堆积。我们通过提出该模型的定性相图来总结我们的发现。