Photoassociation spectroscopy of cold calcium atoms

Photoassociation spectroscopy experiments on Ca-40 atoms close to the dissociation limit 4s4s(1)S(0)-4s4p(1)P(1) are presented. The vibronic spectrum was measured for detunings of the photoassociation laser ranging from 0.6 to 68 GHz with respect to the atomic resonance. In contrast to previous measurements, the rotational splitting of the vibrational lines was fully resolved. Full quantum-mechanical numerical simulations of the photoassociation spectrum were performed which allowed us to put constraints on the possible range of the calcium scattering length between 50a(0) and 300a(0).