Benetzung fester und flüssiger van der Waals-Filme

该项目涉及由分子氢和轻惰性气体形成的弱结合范德瓦尔斯薄膜。这类薄膜通常表现出三点润湿现象，即三点温度Tt以上的液相完全润湿，Tt以下的固相不完全润湿。在最近的实验中，我们已经证明，当通过在衬底上预镀薄的惰性缓冲层来改变吸附-基态相互作用时，这种行为不会发生质的改变。这一结果与当前的理论不同。这种差异的原因尚不清楚：它可能是由于理论处理中的缺陷，但也可能是由于实验中使用的不理想的衬底表面造成的。为了研究这个问题，这里获得的实验结果将与一个理论项目(H.L教授)密切合作进行分析，在该项目中，将进行超越现有唯象理论的计算机模拟。未来要研究的吸附-基质组合也将在此比较的基础上进行选择。为了研究无序和非均匀对固体范德华薄膜润湿行为的影响，重点将重点放在原位制备定义良好的衬底及其表征上。

The project deals with weakly bound van der Waals films formed by molecular hydrogen and the light noble gases. Such films usually display the phenomenon of triple point wetting, i.e. complete wetting of the liquid phase above the triple point temperature Tt and incomplete wetting of the solid phase below Tt. In recent experiments we have shown that this behavior does not change qualitatively when the adsobate-substate interaction is modified by preplating the substrate with thin inert buffer layers. This result is at variance with current theory. The origin for this discrepancy is not clear: it might be due to shortcomings in the theoretical treatment, but may also be caused by the nonideal substrate surfaces used in the experiment. In order to investigate this problem the experimental results obtained here are to be analyzed in close collaboration with a theoretical project (Prof. H. Löwen) in which computer simulations will be carried out which go beyond the existing phenomenogical theory. Future adsorbate-substrate combinations to be studied will also be selected on the basis of this comparison. Moreover, emphasis will be put on the in situ preparation of well-defined substrate and their characterization in order to study the role of disorder and inhomogeneities on the wetting behavior of solid van der Waals films.