Long-range predissociation in two-color photoassociation of ultracold Na atoms

Abstract

We report two-color photo-associative ionization of sodium in a Magneto-Optical Trap. The experimental results yield information on both singly and doubly excited states. We find that the highest bound vibrational levels (v > 20) of the singly-excited 0^- g state predissociate into the 3²P3/2 + 3^²S½(Fg=1) dissociation continuum due to avoided cross- ings of the hyperfine components of this potential with other molecular symmetries. Based on symmetry and energy con- siderations we argue that a doubly-excited 1u state remains autoionizing even when excited only a few GHz above the dis- sociation continuum.