Force fields for silicas and aluminophosphates based onab initiocalculations

Authors address the problem of finding interat. force fields for silicas from ab initio calcns. on small clusters. The force field cannot be detd. from cluster data alone; incorporation of bulk-system information into the force field remains essential. Bearing this in mind, authors derive a force field based on both microscopic (ab initio) and macroscopic (exptl.) data. This force field combines accuracy with transferability to other polymorphs. The possibility of parametrizing other elements is also demonstrated