Electrostatic trapping of metastable NH molecules

TL;DR

This paper demonstrates the successful electrostatic trapping of metastable NH molecules, measuring their trapping time and deducing their radiative lifetime, advancing the control of these radicals for future trapping applications.

Contribution

It reports the first electrostatic trapping of metastable NH molecules and measures their trapping time and radiative lifetime, enabling future magnetic trapping.

Findings

Trapping time of 1.4 seconds for NH molecules.

Lower limit of 2.7 seconds for the radiative lifetime.

Spectral profile measurement of molecules in the trap.

Abstract

We report on the Stark deceleration and electrostatic trapping of $^{14}$NH ($a ^1\Delta$) radicals. In the trap, the molecules are excited on the spin-forbidden $A ^3\Pi \leftarrow a ^1\Delta$ transition and detected via their subsequent fluorescence to the $X ^3\Sigma^-$ ground state. The 1/e trapping time is 1.4 $\pm$ 0.1 s, from which a lower limit of 2.7 s for the radiative lifetime of the $a ^1\Delta, v=0,J=2$ state is deduced. The spectral profile of the molecules in the trapping field is measured to probe their spatial distribution. Electrostatic trapping of metastable NH followed by optical pumping of the trapped molecules to the electronic ground state is an important step towards accumulation of these radicals in a magnetic trap.