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本文用分子束改变平动能的方法，研究了非常态分子ＣＨ４在处于不同表面温度下的稀土Ｌａ薄膜上的激活化学吸附。实验结果表明，当非常态分子的平动能在１０．１～６４．０ｋＪ／ｍｏｌ（对应的垂直分量在７．５～４８．１ｋＪ／ｍｏｌ）之间变化时，只有能量大于５２．３ｋＪ／ｍｏｌ（垂直分量为３９．３ｋＪ／ｍｏｌ）的分子才发生化学吸附，此值称为阈值。当非常态分子的平动能超过阈值时，初始粘着几率Ｓ０随平动能的增大而线性增加。当样品表面温度由５００Ｋ升至７００Ｋ时，虽然样品表面温度升高，但ＣＨ４的阈值能没有改变，且表面的活化能也没有改变。由此说明，阈值能和活化能与样品表面温度无关，它主要由作用于表面上的气体及表面的结构和性质决定。
In this paper, we use the molecular beam to change the translational energy, and study the activation chemisorption of unusual molecular CH4 on rare earth La thin films at different surface temperatures. The experimental results show that when the translational energy of a non-normal molecule changes from 10.1 to 64.0 kJ / mol (corresponding to a vertical component of 7.5 to 48.1 kJ / mol), only the energy is greater than 52.3 kJ / mol (Vertical component of 39.3kJ / mol) of the molecules before chemical adsorption occurs, this value is called the threshold. When the translational energy of unconventional molecules exceeds the threshold, the initial adhesion probability S0 increases linearly with the increase of translational energy. When the sample surface temperature increased from 500K to 700K, although the sample surface temperature increased, but the threshold of CH4 can not change, and the surface activation energy has not changed. Thus, the threshold energy and activation energy are independent of the sample surface temperature, which is mainly determined by the structure and properties of the gas and the surface acting on the surface.