A theor. model is presented to account for the Fano-like interference lineshapes on multiphonon continua in the electronic spectrum of NO in rare-gas solids. The model is based on the coupling of the optical transitions to 1 single local mode, while the latter is coupled to lattice modes. The model complements the original Fano theory by considering the finite lifetime of the continuum states. Lineshapes are simulated for the case of the interference between the B(v = 12) valence level and the C(v = 0) Rydberg level of NO in Kr matrixes and good agreement with exptl. lineshapes is obtained. [on SciFinder (R)]