Inelastic collisions of ultracold triplet Rb$_ extbf{2}$ molecules in the rovibrational ground state

摘要

Exploring inelastic and reactive collisions on the quantum level is a maingoal of the developing field of ultracold chemistry. We present firstexperimental studies of inelastic collisions of metastable ultracold tripletmolecules in the vibrational ground state. The measurements are performed withnonpolar $\textrm{Rb}_2$ dimers which are prepared in precisely-defined quantumstates and trapped in an array of quasi-1D potential tubes. In particular, weinvestigate collisions of molecules in the absolute lowest triplet energy levelwhere any inelastic process requires a change of the electronic state.Nevertheless, we find similar decay rates as for collisions betweenrotationally or vibrationally excited triplet molecules and they are close tothe rates for universal reactions. As anticipated theoretically, the measureddecay rate constants vary considerably when confinement and collision energyare changed. This might be exploited to control the collisional properties ofmolecules.