An ab initio study of the structures and relative stabilities of doubly charged [(NaCl)-m(Na_2]~(2+) cluster ions

摘要

We present ab initio perturbed ion calculationson the structures and reltive stablities of doubly charged [((NaCl)_m(Na)_2]~(2+) cluster ions.The obtained stabilities show excellent agreement with experimental abundances obtained from mass spectra.Those enhanced stabilities are found to be a consequence of highly compact structures that can be built only for certain values of m.Nearly all magic number clusters can be shown to be constructed inone of the twofollowing ways:(a) by adding tri-or penta-atomic chains to two edges of a perfect neutral (NaCl)_n cuboid,withn=m-2 or n=m-4,respectively,or(b) removing a chloride anion from a perfect singly charged (NaCl)_nNa~+ cuboid,with n=m+1.