Structure and stability of (AlN)(n) clusters

AIN and Al2N2 have been observed in the record of time-of-flight mass-spect ra as positive ions. Associating with density functional theory(DFT) B3LYP method with 6-31G* basis set, we have carried out the optimizing calculatio ns of the geometry, electronic state and vibrational frequency for (AIN)(n) (n = 1-15) clusters. moreover, discussed the character of the chemical bon d and thermodynamical stability and explained the experimental mass spectra . The results show that there do not exist Al-Al and N-N bonds and only exi sts Al-N bond in the ground state structures of (AIN)(n) clusters; and the "magical number" regularity of (AIN)(n) is those whose atom number is 4, 8, 12, 16, 20, etc, all of which are times of four.