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本文是在超高真空下,蒸发沉积金属膜,在不同温度下用BA规测量氢的平衡压力。实验温度范围从200℃到-30℃,最低复盖度到θ=0.003(Fe)和0.008(Cr、Ni)。从等量吸附线算出了等量吸附热和25℃的积分吸附熵。从实验值与理论值比较中发现:Ni:θ<0.4,Fe:θ<0.8,Cr一直到θ=1,是定位吸附;Ni:θ>0.4,Fe:θ>0.8时,吸附在这二种金属上的氢有二维移动和垂直于表面的振动。考虑吸附分子间的相互排斥后,认为除了每种金属都有小量高吸附势的吸附位外(少于10％),表面大致是均匀(即不同晶面对吸附热差异不大)的观点能解释吸附熵和吸附热随θ的变化。
In this paper, the ultra-high vacuum deposition of metal film by evaporation, at different temperatures with the BA gauge measuring the equilibrium pressure of hydrogen. The experimental temperatures ranged from 200 ° C to -30 ° C and the minimum coverage was θ = 0.003 (Fe) and 0.008 (Cr, Ni). Equal adsorption heat and integral adsorption entropy at 25 ℃ were calculated from isobaric adsorption line. It is found from the comparison between experimental and theoretical values that Ni: θ <0.4, Fe: θ <0.8, Cr up to θ = 1, and localized adsorption; Ni: θ> 0.4, Fe: Hydrogen on the metal has a two-dimensional movement and perpendicular to the surface of the vibration. Considering the mutual exclusion of adsorbed molecules, it is considered that except that each metal has a small amount of adsorption sites with high adsorption potential (less than 10%) and the surface is substantially uniform (ie, the difference between the different crystal planes is not significant for the adsorption heat) Can explain the adsorption entropy and adsorption heat changes with θ.