Roaming pathways and survival probability in real-time collisional dynamics of cold and controlled bialkali molecules

TL;DR

This study explores the formation and dynamics of long-lived intermediates in cold bialkali molecule collisions, revealing roaming pathways and laser-induced loss mechanisms at ultracold temperatures.

Contribution

It provides the first detailed analysis of roaming pathways and loss probabilities in real-time collisional dynamics of cold bialkali molecules.

Findings

Roaming pathways observed during collision complex formation.

Laser light at 1064 nm causes rapid destruction of the complex.

NaRb molecules are quickly lost in the presence of trapping light.

Abstract

Perfectly controlled molecules are at the forefront of the quest to explore chemical reactivity at ultra low temperatures. Here, we investigate for the first time the formation of the long-lived intermediates in the time-dependent scattering of cold bialkali $^{23}$Na$^{87}$Rb molecules with and without the presence of infrared trapping light. During the nearly 50 nanoseconds mean collision time of the intermediate complex, we observe unconventional roaming when for a few tens of picoseconds either NaRb or Na$_2$ and Rb$_2$ molecules with large relative separation are formed before returning to the four-atom complex. We also determine the likelihood of molecular loss when the trapping laser is present during the collision. We find that at a wavelength of 1064 nm the Na$_2$Rb$_2$ complex is quickly destroyed and thus that the $^{23}$Na$^{87}$Rb molecules are rapidly lost.