We propose a method for copiously producing ultracold ground electronic-state molecules by two-photon absorption to a Rydberg molecular level (that spontaneously radiates to the ground molecular state) during collisions of ultracold atoms in a laser trap. Using the ${\mathrm{Na}}_2$ molecule as an example, the sequential two-photon absorption is via an intermediate high-lying vibrational level of the excited $1_{\mathit{g}}$ state and results in the formation of a given vibrational level of a ${}_{}{}^1{}_{}{}^{}\mathrm{\Pi }_{\mathit{u}}^{}{}_{}{}^{}$ Rydberg molecular state. Realistic calculations demonstrating the validity of the method are presented.

• Received 19 December 1994

DOI:https://doi.org/10.1103/PhysRevA.51.R4317