Photoassociation to the 2(1)Sigma(g)(+) state in ultracold 85Rb2 in the presence of a shape resonance

TL;DR

This paper reports the first observation of photoassociation to specific vibrational levels of ultracold 85Rb2 molecules, highlighting the influence of a shape resonance on the process.

Contribution

It demonstrates photoassociation to the 2(1)Sigma(g)(+) state of 85Rb2 and explores the impact of a shape resonance on the photoassociation dynamics.

Findings

Observed vibrational levels below and above the atomic limit.

Identified the influence of a g-wave shape resonance on photoassociation rates.

Characterized the internuclear region involved in the process.

Abstract

We report the first observation of photoassociation to the 2(1)Sigma(g)(+) state of 85Rb2 . We have observed two vibrational levels (v'=98, 99) below the 5s1/2+5p1/2 atomic limit and eleven vibrational levels (v'=102-112) above it. The photoassociation---and subsequent spontaneous emission---occur predominantly between 15 and 20 Bohr in a region of internuclear distance best described as a transition between Hund's case (a) and Hund's case (c) coupling. The presence of a g-wave shape resonance in the collision of two ground-state atoms affects the photoassociation rate and lineshape of the J'= 3 and 5 rotational levels.