Wetting transitions of 4 He on alkali-metal surfaces from density-functional calculations
Wetting transitions of 4 He on alkali-metal surfaces from density-functional calculations
复制标题
密度泛函计算中 4 He 在碱金属表面的润湿转变
DOI：
10.1103/physrevb.62.17035
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
F. Toigo
中科院分区：
文献类型：
--
作者：
F. Ancilotto;Fabio Faccin;F. Toigo
本文采用非局域自由能密度泛函方法研究了He_4在重碱金属表面的润湿性，该方法能精确描述He_4在0<T<3 K温度范围内的表面性质，给出了He_4在Cs表面的润湿温度和接触角随温度的变化关系，与实验结果符合较好.对于He/Rb系统，我们发现Rb表面的润湿转变发生在T= 1.4K，而实验表明润湿到T=0或在T= 0.3K。我们认为，这种分歧是由于在我们的计算中使用的流体衬底电位的不准确性或衬底粗糙度，这是已知的影响Rb表面的后果，其效果将是降低润湿温度。的润湿转变的敏感性，以氦表面电位强调的He/Rb表面，这可能会证明有争议的实验结果，该系统。
We have studied the wetting properties of He4 adsorbed on the surface of heavy alkali metals by using a non-local free-energy density-functional which describes accurately the surface properties of liquid He4 in the temperature range 0<T<3 K.Our results for He4 on the Cs surface give both the temperature dependence of the contact angle and the wetting temperature in good agreement with the experimental findings. For the He/Rb system we find that a wetting transition on the Rb surface occurs at T=1.4 K, whereas the experiments show either wetting down to T=0 or a wetting transition at T=0.3 K. We suggest that this disagreement is due either to an inaccuracy of the fluid-substrate potential used in our calculations or the consequence of substrate roughness, which is known to affect the Rb surface, and whose effect would be to lower the wetting temperature. The sensitivity of the wetting transition to the He-surface potential are stressed for the He/Rb surface, which may justify the controversial experimental findings for this system.