The CAEDMON Algorithm

Observations about surface energetics can be quantified by applying the CAEDMON algorithm to adsorption data. Isotherms for t—butylamine on graphitized Thornel-300, unsized IM6, and unsized IM6 subjected to plasma treatment were analyzed to obtain adsorption energy profiles. Parameters used in the CAEDMON analysis are presented in Table VI. 

Apart from the original method mentioned above, Morrison and eo-workers [143,144] formulated a new iterative teehnique ealled CAEDMON (Computed Adsorption Energy Distribution in the Monolayer) for the evaluation of the energy distribution from adsorption data without any a priori assumption about the shape of this function. In this case, the local adsorption is calculated numerically from the two-dimensional virial equation. The problem is to find a discrete distribution function that gives the best agreement between the experimental data and calculated isotherms. In this order, the optimization procedure devised for the solution of non-negative constrained least-squares problems is used [145]. The CAEDMON algorithm was applied to evaluate x(fi) for several adsorption systems [137,140,146,147]. Wesson et al. [147] used this procedure to estimate the specific surface area of adsorbents. 

Several numerical procedures for EADF evaluation have also been proposed. Morrison and Ross [19] developed the so-called CAEDMON (Computed Adsorption Energy Distribution in the Monolayer) method. Adamson and Ling [20] proposed an iterative approximation that needs no a priori assumptions. Later, House and Jaycock [21] improved that method and proposed the so-called HILDA (Heterogeneity Investigation at Loughborough by a Distribution Analysis) algorithm. Stanley et al. [22,23] presented two regularization methods as well as the method of expectation maximalization. 

Analysis of Heterogeneity. The monolayer analysis consists of three elements an adsorption isotherm equation, a model for heterogeneous surfaces, and an algorithm such as CAEDMON, which uses the first two elements to extract the adsorptive energy distribution and the specific surface from isotherm data. Morrison and Ross developed a virial isotherm equation for a mobile film of adsorbed gas at submonolayer coverage (6) ... 

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