本篇以蒙地卡羅的方法，研究環戊烷、環己烷、苯、甲苯、對-二甲苯、順-1,4,二甲基環己烷、乙苯等七種分子於Silicalite-1沸石之恆溫吸附。模擬溫度為323，343與373 K，壓力為0.001至600 kPa。
由模擬得知，單位晶格沸石之吸附量與吸附質的大小組態和柔軟度有密切的關係。吸附量均隨溫度之上升而減少，但隨壓力之上升而增加。
當吸附量小於或等於每單位晶格4個分子時，都優先吸附在通道交接處。除了對-二甲苯與乙苯外，吸附熱主要是決定於分子與沸石之間的交互作用，故吸附熱幾乎為定值。對-二甲苯二端之甲基能伸入通道中，造成活化能降低，故吸附熱隨吸附量遞增。乙苯之乙基快速旋轉所形成之立體效應，造成分子間之排斥力，故其吸附熱呈遞減。
當吸附量大於每單位晶格4個分子時，苯、乙苯、對-二甲苯等帶π電子之吸附質，因強烈之分子間作用力而被迫往能量較不利的鋸齒狀通道內吸附，故吸附熱（-ΔH）隨吸附量而快速增加。
吸附熵隨吸附量增加而減小，但吸附自由能則增加。吸附量在每單位晶格3至5分子時，其變化量特別明顯，表示吸附質開始進入空間較狹小的鋸齒狀通道內。

Monte Carlo method has been applied to study the isothermal adsorption of seven cyclic hydrocarbons including cyclopentane, cyclohexane, benzene, toluene, p-xylene, cis-1,4- dimethylcyclohexane and ethylbenzene in silicalite-1 zeolite. Simulations were conducted at temperature 323, 343 and 373 K, with a pressure ranging from 0.001 to 600 kPa.
It’s found that equilibrium loading is closely related to the size, configuration and flexibility of adsorbant. The equilibrium loading decreases with the increase of temperature, but increases with increasing partial pressure of adsorbant.
As the adsorption capacity is no more than 4 molecules per unit cell, adsorbants are preferentially distributed in the channel intersections. Besides p-xylene and ethylbenzene, the adsorption is mainly dominated by the adsorbant- zeolite interactions, therefore the adsorption enthalpy almost constant.
The two methyl groups of p-xylene can enter the channels to reduce the activation energy, therefore the adsorption enthalpy increases with the adsorption capacity. The steric effect caused by the rapid rotation of ethyl group of ethylbenzene increases the repulsions between adsorbants, which reduces the adsorption enthalpy with increasing adsorption capacity.
As the adsorption capacity is greater than 4 molecules per unit cell, the adsorbants with π electrons, such as benzene, ethylbenzene and p-xylene, are forced to be adsorbed in the zigzag channels that are energetically unfavorable, owing to the strong molecular interactions. The adsorption enthalpy thus increases rapidly with the adsorption capacity.
The adsorption entropy decreases with the adsorption capacity, but on the contrary, the free energy increases. The amount of change is mostly prounced as the adsorption capacity is between 3 and 5 molecules per unit cell. It means that adsorbants are accessing narrow zigzag channels.

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