Formation of ultracold Rb 2 molecules in the v′′ = 0 level of the a 3Σ + u state via blue-detuned photoassociation to the 1 3Π g state

Abstract

We report on the observation of blue-detuned photoassociation in Rb2, in which vibrational levels are energetically above the corresponding excited atomic asymptote. 85Rb atoms in a MOT were photoassociated at short internuclear distance to levels of the 13Πg state at a rate of approximately 5 × 104 molecules s−1. We have observed most of the predicted vibrational levels for all four spin–orbit components; 0+g, 0−g, 1g, and 2g, including levels of the 0+g outer well. These molecules decay to the metastable a3Σ+u state, some preferentially to the v′′ = 0 level, as we have observed for photoassociation to the v′ = 8 level of the 1g component.