  We performed an optical spectroscopy study of electronic and magnetic
excitations for a rare-earth system with a single electron quasi-localized in
the f-shell on an ion at high-symmetry crystallographic site in application to
CeB$_{6}$ heavy-fermion metal. We carried out group-theoretical classification
of the electronic crystal field (CF) transitions and assessed their coupling to
light cross-sections for polarization resolved Raman scattering processes. We
discuss applicability of symmetrized Raman susceptibility to studies of exotic
charge and spin high multiplet ordering phases in f-electron systems. We study
temperature effects on intra- and inter-multiplet CF transitions and also on
the coupling between the CF excitations with the lattice vibrations. We
acquired temperature dependence of the low-frequency polarization resolved
Raman response and obtained the static Raman susceptibility for all
Raman-allowed symmetry channels: A$_{1g}$, E$_{g}$, T$_{1g}$, and T$_{2g}$ of
the cubic O$_{h}$ point group. We demonstrate that for CeB$_{6}$ system only
T$_{1g}$-symmetry static Raman susceptibility shows an anomalous temperature
dependence which is consistent with the magnetic susceptibility data measured
by other techniques. This anomalous behavior in the T$_{1g}$-channel signifies
the presence of long wavelength magnetic fluctuations, while the lack of
susceptibility enhancement for all the remaining symmetry channels indicates
that long wavelength charge quadrupole fluctuations at low-temperature are
weak.
