  The experimentally-observed non-trivial electronic structure of Cr$_2$ dimer
has made the calculation of the potential energy curve a theoretical challenge
in the last decades. By matching the perturbation theory at small internuclear
distances $R$, the multipole expansion at large distances $R$ (supposedly both
of asymptotic nature) and by adding a few RKR turning points, extracted from
experimental data, the analytic form for the potential energy curve for the
ground state $X^1\Sigma^+$ of the Cr$_2$ dimer is found for the whole range of
internuclear distances $R$. This has the form of a two-point Pade approximant
and provides an accuracy of 3-4 decimal digits in 29 experimental vibrational
energies. The resulting ground state $X^1\Sigma^+$ potential curve supports
19694 rovibrational states with a maximal vibrational number
$\nu_\text{max}=104$ at zero angular momentum and with a maximal angular
momentum $L_\text{max}=312$ with energies $> 10^{-4}$ Hartree, and additionally
218 weakly-bound states (close to the dissociation limit) with energies $<
10^{-4}$ Hartree.
