  We solve the Bethe-Salpeter equation in order to calculate the spectrum of
pseudoscalar, vector and scalar meson bound states for light as well as heavy
quarks, extending our previous calculation of pseudoscalar mesons. The fermion
propagators appearing in the equation are obtained by solving the
Schwinger-Dyson equation consistently with the Bethe-Salpeter equation, a
procedure necessary for demonstrating the Goldstone nature of the pion in the
chiral limit.
  We probe in our calculations a model for the gluon propagator which leads to
the expected three dimensional potential in configuration space, while
maintaining its known ultraviolet behavior. Our procedure provides a unified
description of both the light and heavy mesons and obeys known relations
derived on the basis of current algebra for light quarks and nonrelativistic
analysis for heavy quarks. The results are in good agreement with experiment
for the mass spectrum and for the pseudoscalar mesons' decay constants. We also
calculate electromagnetic and isospin mass splittings for these mesons.
