Ultracold collisions between Cs atoms and ${\mathrm{Cs}}_{2}$ dimers in the electronic ground state are observed in an optically trapped gas of atoms and molecules. The ${\mathrm{Cs}}_{2}$ molecules are formed in the triplet ground state by cw photoassociation through the outer well of the ${0}_{g}^{\ensuremath{-}}({P}_{3/2})$ excited electronic state. Inelastic atom-molecule collisions converting internal excitation into kinetic energy lead to a loss of ${\mathrm{Cs}}_{2}$ molecules from the dipole trap. Rate coefficients are determined for collisions involving Cs atoms in either the $F=3$ or $F=4$ hyperfine ground state, and ${\mathrm{Cs}}_{2}$ molecules in either highly vibrationally excited states (${v}^{\ensuremath{'}}=32--47$) or in low vibrational states (${v}^{\ensuremath{'}}=4--6$) of the $a\text{ }^{3}\ensuremath{\Sigma}_{u}^{+}$ triplet ground state. The rate coefficients $\ensuremath{\beta}\ensuremath{\sim}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}$ are found to be largely independent of the vibrational and rotational excitation indicating unitary limited cross sections.Ultracold collisions between Cs atoms and ${\mathrm{Cs}}_{2}$ dimers in the electronic ground state are observed in an optically trapped gas of atoms and molecules. The ${\mathrm{Cs}}_{2}$ molecules are formed in the triplet ground state by cw photoassociation through the outer well of the ${0}_{g}^{\ensuremath{-}}({P}_{3/2})$ excited electronic state. Inelastic atom-molecule collisions converting internal excitation into kinetic energy lead to a loss of ${\mathrm{Cs}}_{2}$ molecules from the dipole trap. Rate coefficients are determined for collisions involving Cs atoms in either the $F=3$ or $F=4$ hyperfine ground state, and ${\mathrm{Cs}}_{2}$ molecules in either highly vibrationally excited states (${v}^{\ensuremath{'}}=32--47$) or in low vibrational states (${v}^{\ensuremath{'}}=4--6$) of the $a\text{ }^{3}\ensuremath{\Sigma}_{u}^{+}$ triplet ground state. The rate coefficients $\ensuremath{\beta}\ensuremath{\sim}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}$ are found to be largely independent of the vibrational and rotational excitation indicating unitary limited cross sections.

arXiv:physics/0509123Physical Review LettersJan 19, 2006145 citations

Taming molecular collisions

Bas van de Meerakker

Bulletin of the American Physical SocietyMay 29, 20180 citations

Long-term trapping of Stark-decelerated molecules

Dominik Haas, Claudio von Planta, Thomas Kierspel +2 more

Abstract Trapped cold molecules represent attractive systems for precision-spectroscopic studies and for investigations of cold collisions and chemical reactions. However, achieving their confinement for sufficiently long timescales remains a challenge. Here, we report the long-term trapping of Stark-decelerated OH radicals in their X2Π3/2 (ν = 0, J = 3/2, MJ = 3/2, f) state in a permanent magnetic trap. The trap environment is cryogenically cooled to a temperature of 17 K to suppress black-body-radiation-induced pumping of the molecules out of trappable quantum states and collisions with residual background gas molecules which usually limit the trap lifetime. The cold molecules are thus confined on timescales approaching minutes, an improvement of up to two orders of magnitude compared with room temperature experiments, at translational temperatures of ∼25 mK. The present results pave the way for new experiments using trapped cold molecules in precision spectroscopy, in studies of slow chemical processes at low energies and in the quantum technologies.Abstract Trapped cold molecules represent attractive systems for precision-spectroscopic studies and for investigations of cold collisions and chemical reactions. However, achieving their confinement for sufficiently long timescales remains a challenge. Here, we report the long-term trapping of Stark-decelerated OH radicals in their X2Π3/2 (ν = 0, J = 3/2, MJ = 3/2, f) state in a permanent magnetic trap. The trap environment is cryogenically cooled to a temperature of 17 K to suppress black-body-radiation-induced pumping of the molecules out of trappable quantum states and collisions with residual background gas molecules which usually limit the trap lifetime. The cold molecules are thus confined on timescales approaching minutes, an improvement of up to two orders of magnitude compared with room temperature experiments, at translational temperatures of ∼25 mK. The present results pave the way for new experiments using trapped cold molecules in precision spectroscopy, in studies of slow chemical processes at low energies and in the quantum technologies.

Communications PhysicsAug 29, 201915 citations

Experimental study of cold atom-molecule collisions in a magnetic trap

Sophie Schlunk, Wieland Schöllkopf, Gerard Meijer +1 more

Verhandlungen der Deutschen Physikalischen GesellschaftJan 1, 20050 citations

Ultracold collisions between Cs atoms and

{\mathrm{Cs}}_{2}

dimers in the electronic ground state are observed in an optically trapped gas of atoms and molecules. The

{\mathrm{Cs}}_{2}

molecules are formed in the triplet ground state by cw photoassociation through the outer well of the ${0}_{g}^{\ensuremath{-}}({P}_{3/2})$ excited electronic state. Inelastic atom-molecule collisions converting internal excitation into kinetic energy lead to a loss of

{\mathrm{Cs}}_{2}

molecules from the dipole trap. Rate coefficients are determined for collisions involving Cs atoms in either the

F=3

F=4

hyperfine ground state, and

{\mathrm{Cs}}_{2}

molecules in either highly vibrationally excited states (${v}^{\ensuremath{'}}=32--47$) or in low vibrational states (${v}^{\ensuremath{'}}=4--6$) of the $a\text{ }^{3}\ensuremath{\Sigma}_{u}^{+}$ triplet ground state. The rate coefficients $\ensuremath{\beta}\ensuremath{\sim}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}$ are found to be largely independent of the vibrational and rotational excitation indicating unitary limited cross sections.