AbstractResonance Raman excitation profiles for a substituted phthalocyanine dispersed as a polycrystalline powder in a silver disc were compared with those for a Langmuir–Blodgett (LB) multilayer of the same material on a silicon surface. There is a strong angular dependence of the efficiency of the scattering process. The LB profiles are strongly influenced by the electronic fields from the smooth semiconducting silicon surface, which gives rise to increased π‐π* energy separation and comparatively efficient scattering from upper vibronic s