PNNL

Abstract

The structure and electronic properties of the Al8N- and Al8N clusters were investigated by combined photoelectron spectroscopy and ab initio studies. Congested photoelectron spectra were observed and experimental evidence was obtained for the presence of multiple isomers for Al8N- Global minimum searches revealed several structures for Al8N- with close energies. The calculated vertical detachment energies of the two lowest-lying isomers, which are of C2v and Cs symmetry, respectively, were shown to agree well with the experimental data. Unlike the three-dimensional structures of Al6N- and Al7N-, in which the dopant N atom has a high coordination number of 6,the dopant N atom in the two low-lying isomers of Al8N- has a lower coordination number of 4 and 5, respectively. The competition between the Al–Al and Al–N interactions are shown to determine the global minimum structures of the doped aluminum clusters and results in the structural diversity for both Al8N- and Al8N. © 2009 American Institute of Physics