Additional constraints in adsorption-desorption kinetics

In this work, the adsorption-desorption kinetic in the framework of the lattice gas model is analyzed. The transition probabilities are written as an expansion of the occupation configurations. Due to that, the detail balance principle determine half of the adsorption $A_i$ and desorption $D_i$ coefficients, consequently, different functional relations between them are proposed. Introducing additional constrains, it is demonstrated that when those coefficients are linearly related through a parameter $\gamma$, there are values of lateral interaction $V$, that lead to anomalous behavior in the adsorption isotherms, the sticking coefficient and the thermal programmed desorption spectra. Diagrams for the allowed values of $V$ and $\gamma$ are also shown. Alternatively, a more reliable formulation for the adsorption desorption kinetic based on the transition state theory is introduced. In such way the equilibrium and non equilibrium observables do not present anomalous or inconsistent behavior.

Figure 1

Diagram $\gamma$ versus $\beta V$ corresponding to (a) $K1$ and (b) $K2$ proposed kinetics.

Figure 2

Adsorption isotherms for different values of the parameter $\gamma$ and for two linear proposed kinetics. (a) Attractive and (b) repulsive lateral interaction.

Figure 3

Sticking coefficients for different values of the parameter $\gamma$ and for two linear proposed kinetics. (a) Attractive and (b) repulsive lateral interaction.

Figure 4

Immobile TPD for different values of the parameter $\gamma$ and for two linear proposed kinetics. (a) Attractive and (b) repulsive lateral interaction.

Figure 5

(a) Adsorption isotherms, (b) sticking coefficients, and (c) immobile TPD, for attractive (dot), repulsive (dash), and null (line) interaction, using the inverse relation $L3$.