  We give a short and basic introduction to our covariant
Dyson-Schwinger-Bethe-Salpeter-equation approach using a rainbow-ladder
truncated model of QCD, in which we investigate the leptonic decay properties
of heavy quarkonium states in the pseudoscalar and vector channels. Comparing
the magnitudes of decay constants, we identify radial 1-- excitations in our
calculation with experimental excitations of J/\Psi and \Upsilon. Particular
attention is paid to those states regarded as D-wave states in the quark model.
We predict e+e- decay width of the \Upsilon(1^3D_1) and \Upsilon(2^3D_1) states
of the order of ca. 15 eV or more. We also provide a set of predictions for
decay constants of pseudoscalar radial excitations in heavy quarkonia.
