Collisional decay of ${}^{87}\mathrm{Rb}$ Feshbach molecules at $1005.8\mathrm{G}$

We present measurements of the loss-rate coefficients $K_{\mathit{am}}$ and $K_{\mathit{mm}}$ caused by inelastic atom-molecule and molecule-molecule collisions. A thermal cloud of atomic ${}^{87}\mathrm{Rb}$ is prepared in an optical dipole trap. A magnetic field is ramped across the Feshbach resonance at $1007.4\mathrm{G}$. This associates atom pairs to molecules. A measurement of the molecule loss at $1005.8\mathrm{G}$ yields $K_{\mathit{am}}=2\times {10}^{-10}{\mathrm{cm}}^3∕\mathrm{s}$. Additionally, the atoms can be removed with blast light. In this case, the measured molecule loss yields $K_{\mathit{mm}}=3\times {10}^{-10}{\mathrm{cm}}^3∕\mathrm{s}$.

Figure 1

Loss of molecules after blasting away the atoms. The solid line shows a fit of Eq. (4) to the data, yielding $K_{\mathit{mm}}$.

Figure 2

Loss of molecules in the presence of the atoms. The solid line shows a fit of Eq. (4) to the data, yielding $K_{\mathit{am}}$. Clearly, the loss here is much faster than in Fig. 1.