# Photo-induced two-body loss of ultracold molecules

## TL;DR

This study reveals that laser-induced electronic excitation causes two-body loss in ultracold NaK molecules, challenging previous assumptions about three-body loss limitations and suggesting ways to suppress these losses.

## Contribution

It demonstrates that laser excitation, not sticky collisions, is responsible for two-body loss, providing a new understanding of loss mechanisms in ultracold molecules.

## Key findings

- Electronic excitation causes observed two-body loss.
- Longer laser wavelengths can reduce losses.
- Sticking times are shorter than previously thought.

## Abstract

The lifetime of nonreactive ultracold bialkali gases was conjectured to be limited by sticky collisions amplifying three-body loss. We show that the sticking times were previously overestimated and do not support this hypothesis. We find that electronic excitation of NaK+NaK collision complexes by the trapping laser leads to the experimentally observed two-body loss. We calculate the excitation rate with a quasiclassical, statistical model employing ab initio potentials and transition dipole moments. Using longer laser wavelengths or repulsive box potentials may suppress the losses.