The spectroscopic parameters (R-e, D-e, omega (e)) for the ground state of the weakly bound Zn-rare gas (RG) van der Waals molecules have been derived from ab initio calculated potential curves. The potential curve calculations have been carried out using the coupled-cluster with single and double excitations and perturbative contribution of connected triple excitations (CCSD(T)) method for the 20 electrons of Zn and the valence electrons of RG atom, while the Zn20+ and RG(8-) cores are replaced by ab initio quasirelativistic energy-consistent pseudopotentials. The theoretical potentials are discussed in the context of available experimental data. Very good agreement between theory and experiment has been obtained.