Understanding the Site Selectivity in Small-SizedNeutral and Charged Aln(4 ≤ n≤ 7) Clusters Using Density Functional Theory BasedReactivity Descriptors: A Validation Study on Water Molecule Adsorption.

Aluminum clusters are now technologicallyimportant due to theirhigh catalytic activity. Our present study on the small-sized aluminumclusters applies density functional theory (DFT)-based reactivitydescriptors to identify potential sites for adsorption and eventualchemical reaction. Depending on symmetry, susceptibility of varioustype of reactive sites within a cluster toward an impending electrophilicand/or nucleophilic attack is predicted using the reactivity descriptors.In addition, the study devises general rules as to how the size, shape,and charge of the cluster influences the number of available sitesfor an electrophilic and/or nucleophilic attack. The predictions byreactivity descriptors are validated by performing an explicit adsorptionof water molecule on Al clusters with four atoms. The adsorption studiesdemonstrate that the most stable water–cluster complex is obtainedwhen the molecule is adsorbed through an oxygen atom on the site withthe highest relative electrophilicity. [ABSTRACT FROM AUTHOR]