X-ray specular-reflectivity study of the liquid-vapor density profile of 4He.
X-ray specular-reflectivity study of the liquid-vapor density profile of 4He.
复制标题
4He 液体-蒸汽密度分布的 X 射线镜面反射率研究。
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
Ocko
中科院分区：
文献类型：
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作者：
Lurio;Rabedeau;Pershan;Silvera;Deutsch;Kosowsky;Ocko
用X射线镜面反射率法测量了氦-气界面密度分布。对吸附在原子扁平硅衬底上的氦的厚膜进行了测量。测量了氦-气界面和硅-氦界面反射的干涉，得到了氦-气界面复散射振幅的幅值和相位。研究了在1.1~3.0K温度范围内，厚度在15A~220A之间变化的薄膜。在[italT]=1.13K时，薄膜厚度为215A，界面宽度为9.2[+-]1A。在1.1-1.8K温度范围内测得的界面宽度没有明显变化。对测量结果的分析表明，界面是不对称的，密度衰减成蒸汽的幅度更大。用量子化毛细管波理论由有限温度测量外推的零-K界面宽度为7.6[SUB[负]2][SUP+1]A。
The helium liquid-vapor interfacial density profile has been measured with x-ray specular reflectivity. Measurements were performed on thick films of helium adsorbed onto atomically flat silicon substrates. Both the amplitude and the phase of the complex scattering amplitude of the helium-vapor interface were obtained from measured interference between reflections from the helium liquid-vapor interface and the silicon-helium interface. Films whose thickness varied from 15 A to 220 A over a range of temperatures from 1.1 K to 3.0 K were studied. At [ital T]=1.13 K the film thickness is 215 A and the interfacial width is 9.2[plus minus]1 A. No significant variation was seen in the interfacial widths measured at temperatures between 1.1 K and 1.8 K. Analysis of these measurements indicates that the interface is asymmetric, with the decay of the density into the vapor having the sharper falloff. The zero-K interfacial width extrapolated from the finite-temperature measurements with a quantized capillary-wave theory is 7.6[sub [minus]2][sup +1] A.