Abstract

With a simple Franck - Condon pumping scheme Na₂ molecules are prepared with large internuclear distances. At the atomic asymptote 3s + 3p the vibrational, rotational, and hyperfine structure is measured with high precision, and it enables us to derive the dipole-dipole interaction and the dissociation energy using atomic data from other sources. The observed molecular levels were fitted to adiabatic asymptotic potentials that were derived from the diagonalization of the Hamiltonian with the R-dependent electrostatic dipole-dipole term, the atomic spin-orbit, and hyperfine interactions. The higher order terms of the electrostatic coupling and the exchange force lay no significant role in our study, and even for internuclear distances up to 300 Å no retardation was observed within error limits.

© 1996 Optical Society of America