Angstrom Porosimety with quantum Herium

氦原子是最小的球形单原子分子，与任何固体表面非特异性地相互作用。4.2 K He吸附是测定埃孔结构的有效方法。对活性炭体系进行了4.2 K的He吸附。用理论吸附He密度（0.202gml^<-1>）和液体N_2密度（0.807gml^<-1>）分别与氮气吸附等温线进行了比较。低相对压力区He的吸附量远大于N_2的吸附量。这表明He具有更好的可及性和加速双层吸附。采用Dubinin-Radushukevich图对He吸附等温线进行了分析，提出了利用高斯分布函数和Dubinin-Stoeckli关系确定He吸附等温线埃孔径分布的方法。这种分析方法对测定活性炭的孔径分布是非常有效的。它可以显示用氮气吸附法无法评价的埃孔的存在。然而，这种方法的应用仅限于活性炭系统。我们利用孔隙中He原子的电位分布和分布进行了更一般的分析。我们将He在平面上吸附的Steele方法应用于埃斯特孔分析。利用Lennard-Jones势作为孔宽的函数计算了He原子与孔的势分布。这种潜在的轮廓和统计考虑导致孔隙中可能存在He原子。因此，我们可以用观察到的吸附等温线的最佳拟合程序来确定微孔大小的分布。结果表明，这种具有普遍适用性的分子势吸附法是一种很有希望的表征埃孔的方法。采用大正则蒙特卡罗（GCMC）计算机模拟分析了He吸附等温线。然而，用GCMC方法确定埃孔径分布的发展还需要更多的时间。少

A He atom is the smallest spherical monoatomic molecule and interacts nonspecifically with any solid surface. He adsorption at 4.2 K is an effective method for determination of Angstrom pore structures. The He adsorption at 4.2 K was applied to activiated carbon system. The adsorption isotherms were compared with N_2 adsorption isotherms using the theoretical adsorbed He density (0.202gml^<-1>) on the flat surface and the liquid N_2 density (0.807gml^<-1>) , respectively. The amount of He adsorption was much greater than that of N_2 in the low relative pressure region. This suggests better accessibility and accelerated bilayr adsorption of He. The He adsorption isotherm was analyzed by the Dubinin-Radushukevich plot and we developed the determination method of the Angstrom pore size distribution from the He adsorption isotherm using the Gaussian distribution function and the Dubinin-Stoeckli relation. This analysis was quite effective for determination of the Angstrom pore size distrib … More ution for activated carbon. It can show presence of the Angstrom pores which cannot be evaluated by N_2 adsorption method. However, the application of this approach is limited to activated carbon system. We developed a more general analysis using the potential profile and distribution of a He atom in the pore. We applied the Steele approach to He adsorption on the flat surface to the Angstrom pore analysis. The potential profile of a He atom with the pore was determined by calculation using the Lennard-Jones potential as a function of the pore width. This potential profile and statistical considerations lead to a possible population of He atoms in the pore. Hence, we can determine the micropore size distribution by the best fit procedure to the observed adsorption isotherm. It was shown that this molecular potential approach for He adsorption having a general applicability is a hopeful method for Angstrom pore characterization. Also the Grand Canonical Monte Calro (GCMC) computer simulation was applied to analyze the He adsorption isotherm. However, it will take more time to establish the development of the Angstrom pore size distribution-determination with the GCMC method. Less