  A systematic description of multipole degrees of freedom is discussed on the
basis of the Stevens' operator-equivalent technique. The generalized Stevens'
multiplicative factors are derived for all of the electric and the magnetic
multipoles relevant to f-electron systems. With extensive use of the Stevens'
factors, we express the spatial dependences of the electric and the magnetic
fields, and the electric and the magnetic charge densities of localized f
electrons. The latter is utilized to draw wave functions including their
magnetic profile in addition to their shape with the charge density. The
definite relation between the operators as quantum-mechanical variables in a
multipole exchange model and the multipole moments in expansion of
electromagnetic fields is given. The general treatments for the exchange model
with the RPA susceptibility and the Ginzburg-Landau free-energy expansion are
discussed, using CexLa1-xB6 as a typical example. The representative formula of
the vector spherical harmonics are summarized, which are suitable basis for
vector fields in the spherical expansion.
