Cluster modeling of metal oxides: how to cut out a cluster?

Three principles have been proposed for the cluster modeling of metal oxides, i.e. the neutrality principle, stoichiometry principle and coordination principle. A stoichiometric cluster model is recommended, for it possesses the correct atomic ratio of bulk solid and it automatically meets the requirement of neutrality. Particular attention has been focused on how to cut out a stoichiometric cluster which has as few dangling bonds as possible so as to fulfill the requirement of the coordination principle. A case study for the applications of these three principles to the modeling of ZnO solid has shown their efficiency in setting up a better cluster model of a given size.