  The electromagnetic radiative transition widths for heavy quarkonia, as well
as digamma and digluon decay widths, are computed in the framework of the
extended harmonic confinement model (ERHM) and Coulomb plus power potential
(CPP$_\nu$) with varying potential index $\nu$. The outcome is compared with
the values obtained from other theoretical models and experimental results.
While the mass spectra, digamma and digluon widths from ERHM as well as
CPP$_{\nu=1}$ are in good agreement with experimental data, the electromagnetic
transition widths span over a wide range for the potential models considered
here making it difficult to prefer a particular model over the others because
of the lack of experimental data for most transition widths.
