Isomers and transition states of the Na4+ clusters: ab initio studies of geometries and absorption spectra

Stable isomers, transition states and their photoabsorption spectra for the Na4+ cluster were obtained by ab initio MRCI computations. Three stable geometries of symmetry C2v, D2h and D2d, and two transition states of symmetry Cs and C2 were determined. The D2d configuration is a new geometry not formerly obtained in ab initio computations. The photoabsorption spectra of the three isomers and the transition states were utilized to interpret experimental absorption data.