Molecular dynamics simulations are reported for the structural and thermodynamic properties of submonolayer xenon adsorbed on the (111) surface of platinum for temperatures up to the (apparently incipient) triple point and beyond. While the motion of the atoms in the surface plane is treated with a standard two-dimensional molecular dynamics simulation, the model takes into consideration the thermal excitation of quantum states associated with surface-normal dynamics in an attempt to describe the apparent smoothing of the corrugation with increasing temperature. We examine the importance of this thermal smoothing to the relative stability of several observed and proposed low-temperature structures. Structure factor calculations are compared to experimental results in an attempt to determine the low temperature structure of this system. These calculations provide strong evidence that, at very low temperatures, the domain wall structure of a xenon monolayer adsorbed on a Pt(111) substrate possesses a chaotic-like nature, exhibiting long-lived meta-stable states with pinned domain walls, these walls having narrow widths and irregular shapes. This result is contrary to the standard wisdom regarding this system, namely, that the very low temperature phase of this system is a striped incommensurate phase. We present the case for further experimental investigation of this and similar systems as possible examples of chaotic low temperature phases in two dimensions.

中文翻译：

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Pt（111）上亚单分子层Xe的模拟：低温混沌相的情况

分子动力学模拟报道了在温度高达（显然是初期的）三点及更高温度时，吸附在铂（111）表面上的亚单层氙的结构和热力学性质。尽管使用标准的二维分子动力学模拟处理了表面中原子的运动，但是该模型考虑了与表面法向动力学相关的量子态的热激发，以试图描述波纹的表观平滑度。随着温度升高。我们研究了这种热平滑对观察到的和提出的几种低温结构的相对稳定性的重要性。将结构因子计算与实验结果进行比较，以尝试确定该系统的低温结构。这些计算提供了有力的证据，表明在非常低的温度下，吸附在Pt（111）衬底上的氙单层的畴壁结构具有混沌性质，表现出具有固定畴壁的长寿命亚稳态，这些壁具有窄的宽度和不规则的形状。该结果与关于该系统的标准观点相反，即该系统的非常低的温度阶段是条带状的不相称的阶段。我们提出了对该系统和类似系统进行进一步实验研究的案例，以作为二维低温混沌相的可能示例。呈现出具有固定畴壁的长寿命亚稳态，这些壁具有窄的宽度和不规则的形状。该结果与关于该系统的标准观点相反，即该系统的非常低的温度阶段是条带状的不相称的阶段。我们提出了对此和类似系统进行进一步实验研究的案例，作为二维低温混沌相的可能示例。呈现出具有固定畴壁的长寿命亚稳态，这些壁具有窄的宽度和不规则的形状。该结果与关于该系统的标准观点相反，即该系统的非常低的温度阶段是条带状的不相称的阶段。我们提出了对该系统和类似系统进行进一步实验研究的案例，以作为二维低温混沌相的可能示例。