Spectroscopy of Quasibound and Long-Range Rydberg States of Ultracold 85Rb2

Ultracold atomic physics offers an experimentalist the opportunity to perform sensitive tests and measurements that are not possible at higher temperatures. In this case it allows for access to molecular states, through photoassociation, that are inaccessible to conventional techniques. We use photoassociation to measure quasi-bound levels of the 2 1Σg+ state of 85Rb2 . With these data, we examine a coupling between the short-range Hund’s case (c) 2 (0g+ ) component and the long-range 2 (1g ) state, which corresponds to the 1 1Πg state. A second experiment studies the mechanism of short-range photoassociation and finds our simple model to have strong predictive power. In a third experiment, we photoassociatively form vibrationally excited a 3 Σu+ molecules. We then excite these molecules using a frequency-doubled pulse-amplified CW laser to create low-n long-range Rydberg states of 85Rb2 . Autoionization and ion detection of these states gives high-resolution spectra, which are compared to theoretical potential curves