The coupling between the intramolecular vibrational modes and the dope
d conduction electrons in M3C60 is studied by a calculation of the ele
ctronic contributions to the phonon self-energies. The calculations ar
e carried out for an orientationally ordered reference solid with symm
etry Fm3BARm and for a model with quenched orientational disorder on t
he fullerene sites. In both cases, the dispersion and symmetry of the
renormalized modes is governed by the electronic contributions. The cu
rrent-current correlation functions and frequency-dependent conductivi
ty through the midinfrared are calculated for both models. In the diso
rdered structures, the renormalized modes derived from even-parity int
ramolecular phonons are resonant with the dipole excited single-partic
le spectrum, and modulate the predicted midinfrared conductivity. The
spectra for this coupled system are calculated for several recently pr
oposed microscopic models for the electron-phonon coupling, and a comp
arison is made with recent experimental data which demonstrate this ef
fect.