Dynamics of the X-ray clusters Abell 222, Abell 223 and Abell 520

We present the results of a dynamical analysis of three rich, X-ray luminou s galaxy clusters, Abell 222, Abell 223 and Abell 520, that are at intermed iate redshifts. Our study is based on radial velocities for 71 cluster memb ers, respectively 30 for A 222, 20 for A 223 and 21 for A 520, measured fro m spectra obtained at the Canada-France-Hawaii Telescope, the European Sout hern Observatory, and the Pic du Midi Observatory, and supplemented with ra dial velocities from the literature. A 222 galaxies have slightly higher ve locities than those of A 223, with hi-weighted mean velocity of V-bi = 6424 2 +/- 194 km s(-1) for A 222, and of V-bi = 63197 +/- 266 km s(-1) for A 22 3. The velocity dispersions of the two clusters are about the same: sigma(b i) = 1013 +/- 150 km s(-1) and sigma(bi) = 1058 +/- 160 km s(-1) for A 222 and A 223, respectively. For A 520 we obtain V-bi = 60127 +/- 284 km s(-1) with sigma(bi) = 1250 +/- 189 km s(-1). We also give mass and mass-luminosi ties ratio estimates for each cluster separately. We argue that these clust ers are presently undergoing strong dynamical evolution and that A 222 and A 223 will probably merge in the future. We have applied a Principal Compon ent Analysis to a sample of 51 CFHT spectra to produce a spectral classific ation for these galaxies. This classification has allowed us to show that t he morphological and kinematical segregations were already established in t hese intermediate redshift clusters.