  Dyson-Schwinger equations provide a prominent approach to physics of strong
interactions. To reproduce the hadronic phenomenology well, the Dyson-Schwinger
approach in the rainbow-ladder approximation must employ an effective
interaction between quarks which is fairly strong at intermediate (Q^2 approx.
0.5 GeV^2) spacelike transferred momenta. We have recently proposed that such
an interaction may originate from the dimension 2 gluon condensate <A^2> which
has recently attracted much attention, and showed that the resulting effective
running coupling leads to the sufficiently strong dynamical chiral symmetry
breaking and successful phenomenology at least in the light sector of
pseudoscalar mesons. In the present paper, we give a more detailed
investigation of the parameter dependence of these results.
