  The potential curve, dissociation energy, equilibrium internuclear distance,
and spectroscopic constants for the ground state of the Ca2 molecule are
calculated with the help of the generalized relativistic effective core
potential method which allows one to exclude the inner core electrons from the
calculations and to take the relativistic effects into account effectively.
Extensive generalized correlation basis sets were constructed and employed. The
scalar relativistic coupled cluster method with corrections for high-order
cluster amplitudes is used for the correlation treatment. The obtained results
are analyzed and compared with the experimental data and corresponding
all-electron results.
