  We suggest a framework based on the rainbow approximation to the
Dyson-Schwinger and Bethe-Salpeter equations with effective parameters adjusted
to lattice QCD data to calculate the masses of the ground and excited states of
pseudo-scalar glueballs. The structure of the truncated Bethe-Salpeter equation
with the gluon and ghost propagators as solutions of the truncated
Dyson-Schwinger equations is analysed in Landau gauge. Both, the Bete-Salpeter
and Dyson-Schwinger equations, are solved numerically within the same
rainbow-ladder truncation with the same effective parameters which ensure
consistency of the approach. We found that with a set of parameters, which
provides a good description of the lattice data within the Dyson-Schwinger
approach, the solutions of the Bethe Salpeter equation for the pseudo-scalar
glueballs exhibit a rich mass spectrum which also includes the ground and
excited states predicted by lattice calculations. The obtained mass spectrum
contains also several intermediate excitations beyond the lattice approaches.
The partial Bethe-Salpeter amplitudes of the pseudo-scalar glueballs are
presented as well.
