Based on the density functional theory with gradient corrected exchange-correlation potential, we have studied the atomic structures and electronic properties of Al7IN (N = 1, 2,3) and Al13I clusters. The atomic structure of Al-7 is not significantly changed by doping three iodine atoms. However, the adsorption positions of iodine atoms are dependent on the charge state of Al7In cluster. Analyzes of the electronic structure of Al7In- cluster shows that some of the electrons are transferred to iodine atom, although most electrons in the highest occupied molecular orbits distribute around the aluminum atoms. (c) 2005 Elsevier B.V. All rights reserved.