Photoassociative spectroscopy of 1g, 0+u, and 0−g states of Na2

We use photoassociation of ultracold Na to study transitions from free atoms to bound molecules. We obtain rovibrational spectra of the 1g, the 0+u, and, for the first time, the 0−g ‘‘purely long-range’’ state of Na2, all of which dissociate to Na(3 2S1/2)+Na(3 2P3/2).