Influence of the electron damping on the properties of intermediate valence systems

The influence of conduction electron damping on the possibility of excitonic coupling in the intermediate valence systems is considered. The scattering by the internal degrees of freedom of f?-shells is shown to be the main mechanism for this damping. It is shown that both the excitonic energy gap and the damping are proportional to s-f? Coulomb integral, so the scattering considered prevents s- and f?-electrons from anomalous coupling. The growth of the resistivity near the point of valence change can be understood as the manifestation of this scattering.