Creation of ultracold $^{87}$RbCs molecules in the rovibrational ground state

TL;DR

This paper reports the successful creation of over 1000 ultracold RbCs molecules in their ground state, with detailed measurements of their binding energy, vibrational splitting, and electric dipole moment, advancing ultracold molecule research.

Contribution

The study demonstrates a reliable method to produce ground-state RbCs molecules with high dipole moments, including precise spectroscopic measurements and a large sample size.

Findings

Over 1000 ultracold RbCs molecules created in the ground state.

Measured binding energy as 3811.576 cm$^{-1}$.

Electric dipole moment of 1.225 D in the rovibrational ground state.

Abstract

We report the creation of a sample of over 1000 ultracold $^{87}$RbCs molecules in the lowest rovibrational ground state, from an atomic mixture of $^{87}$Rb and Cs, by magnetoassociation on an interspecies Feshbach resonance followed by stimulated Raman adiabatic passage (STIRAP). We measure the binding energy of the RbCs molecule to be $h c \times 3811.576(1)$ cm$^{-1}$ and the $|v''=0, J''=0>$ to $|v''=0, J''=2>$ splitting to be $h \times 2940.09(6)$ MHz. Stark spectroscopy of the rovibrational ground state yields an electric dipole moment of 1.225(3)(8) D, where the values in parentheses are the statistical and systematic uncertainties, respectively. We demonstrate that a space-fixed dipole moment of 0.355(2)(4) D is accessible in RbCs, which is substantially higher than in previous work.