First-principles study of structures and electronic properties of cadmium sulfide clusters

The lowest-energy structures and the electronic properties of Cd_nS_n (n=1-8) clusters have been studied by using density-functional theory simulating package DMol^3 in the generalized gradient approximation (GGA). The ring-like structures are the lowest-energy configurations for n=2, 3 and the three-dimensional spheroid configurations for n=4-8. The three-dimensional structures may be considered as being built from the Cd_2S_2 and Cd_3S_3 rings. Compared to the previous reports, we have found the more stable structures for Cd_nS_n(n=7,8). Calculations show that the magic numbers of Cd_nS_n (n=1-8) clusters are n=3 and 6. As cluster size increases, the properties of Cd_nS_n clusters tend to bulk-like ones in binding energy per CdS unit and Mulliken atomic charge, obtained by comparing with the calculated results of the wurtzite and zinc blende CdS for the same simulating parameters.