We study the photoassociative process between cold atoms and a surface. A mechanism to confine free cold atoms in a planar waveguide, characterized by the long-range atom-surface van der Waals potential and based on radiative transitions, is presented. We propose that the vibrational states of this potential can be probed by reflection spectroscopy, giving information about the $C_3$ van der Waals coefficients.

• Received 29 October 1999

DOI:https://doi.org/10.1103/PhysRevA.62.013410