Theoretical study of lower electronic excitation spectra of [(Re6S8)Cl6]3−

We report the electronic structure of [(Re6S8)Cl6]3− using theoretical calculations. Since the lowest 2Au and 2Ag states were energetically very close to each other, we employed single and double excitation configuration interaction method and coupled pair approximation to specify the ground state. It was settled to the 2Au state. Wavefunctions of many lower excited states were obtained by the Tamm–Dankoff type CI. Calculated oscillator strength distribution was in good agreement with observed absorption intensity curve. Those excited states lower than 2.3 eV were described mainly as intra ligands transition and those higher than 2.3 eV were charge transfer transition from ligands to metals.