Prediction of the extraction energy of an atom from the surface of Fe-Cr alloys using topological descriptors

A 3D model for simulating the passivation of iron-chromium alloys has been developed previously. This paper describes the attempts to estimate the probabilities of dissolution used in the model from the energy of extraction of Fe or Cr atoms according to their chemical environment. Quantum chemistry calculations have been performed to estimate the energy of extraction of Fe or Cr from the cluster for various topological environments of the atom to be extracted. Using the obtained results, a simple multilinear correlation between the energy of extraction of an atom and its environment has been developed. Such a relation will allow us to do more rapid calculations of the energy of extraction for any topology, which can be included in the simulation. The correlation used topological descriptors describing, in a relevant way, the environment of an atom to be extracted. At first, we tested the descriptors connected to the location of the extracted atom in relation with its neighbors. Then, we took into account the parameters describing only the distribution of the neighbors among them, which leads to the autocorrelation function of the cluster. Finally, we combined these two types of descriptors. (C) 2002 Elsevier Science B.V. All rights reserved.