A study of the 1B2 excited state geometries of the metal-metal quadruply bonded compounds Mo2X4(PMe3)4 (X  Cl, Br or I) Original Research Article

The excited state geometries of the metal-metal quadruply bonded compounds Mo2X4(PMe3)4 (X  Cl, Br or I) have been studied by means of resonance Raman and absorption spectroscopy. A fit of the parameters of a simple theoretical model to the experimental data indicates that the metal-metal bond increases some 10 pm on excitation to the 1B2 (δδ∗) state, whereas other geometric changes are small. Furthermore, the phenomenological lifetime factor of the excited state, Γ, is found to be dependent on the vibrational quantum number, ν, of this state.