Electronic spectra and resonance Raman excitation profiles of M(L—L)2M(L—L)2X2(ClO4)4: bulk and small particles

The optical properties of compounds M(L—L)2M(L—L)2X2(ClO4)4(where M is Pd or Pt, L—L is 1,2-diaminoethane or 1,2-diaminopropane and X is Cl or Br) have been studied. The single-crystal and the polycrystalline-pellet reflectance spectra show semiconductor behaviour in one dimension. The resonance Raman excitation profiles for a polycrystalline pellet occur near the gap frequency of the semiconductor as predicted theoretically. The absorption and light scattering spectra and the excitation profiles of small particles show size, shape and aggregation effects.