Within a recently proposed variational approach it has been shown that, in
La(1-x)A(x)MnO(3) perovskites with 0<x<0.5, near the metal-insulator transi
tion, the combined effect of the magnetic and electron-phonon interactions
pushes the system toward a regime of two coexisting phases: a low electron
density one made by itinerant large polarons forming ferromagnetic domains
and a high electron density one made by localized small polarons giving ris
e to paramagnetic or antiferromagnetic domains depending on temperature, Em
ploying the above-mentioned variational scheme, in this paper spectral and
optical properties of manganites are derived for x=0.3 at different tempera
tures. It is found that the phase separation regime induces a robust pseudo
gap in the excitation spectrum of the system. Then the conductivity spectra
are characterized by a transfer of spectral weight from high to low energi
es, as the temperature T decreases. In the metallic ferromagnetic phase, at
low T two types of infrared absorption come out: a Drude term and a broad
absorption hand due respectively to the coherent and incoherent motion of l
arge polarons. The obtained results turn out in good agreement with experim
ents.