Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Cold inelastic collisions between lithium and cesium in a two-species magneto-optical trap

Schlöder, U, Engler, H, Schünemann, U, Rudolf Grimm, Matthias Weidemüller

Published Jan 1, 1999• 28 citations
OpenAlex

Abstract

We investigate collisional properties of lithium and cesium which are simultaneously confined in a combined magneto-optical trap. Trap-loss collisions between the two species are comprehensively studied. Different inelastic collision channels are identified, and inter-species rate coefficients as well as cross sections are determined. It is found that loss rates are independent of the optical excitation of Li, as a consequence of the repulsive Li$^*$-Cs interaction. Li and Cs loss by inelastic inter-species collisions can completely be attributed to processes involving optically excited cesium (fine-structure changing collisions and radiative escape). By lowering the trap depth for Li, an additional loss channel of Li is observed which results from ground-state Li-Cs collisions changing the hyperfine state of cesium.

Related papers

A study of collisional trap loss in ultra-cold trapped lithium-6 and lithium-7

Nicholas W. M. Ritchie

Measurements of the trap loss rate in ultra-cold magneto-optically trapped $\\sp6$Li and $\\sp7$Li are presented and compared. Clear evidence is presented for two different trap loss mechanisms involving inelastic collisions between one ground state atom and one excited state atom. The fine-structure changing (FSC) mechanism, in which the excited state atom changes fine-structure level during a collision, is seen to dominate the rate at low trap laser intensities. However, as the intensity is increased, the trap becomes sufficiently deep to be able to contain the products of FSC collisions and this mechanism no longer contributes to trap loss. It is a unique aspect of Li that the energy imparted to an atom in a FSC collision is in a range that may be recaptured with experimentally attainable trap parameters. When the products of all FSC collisions remain trapped, only the radiative escape (RE) trap loss mechanism, due to the emission of a less energetic photon than the initial excitation photon, contributes to the trap loss rate. At small detunings, the rate of the RE trap loss mechanism is seen to be over two orders-of-magnitude smaller than the FSC rate. The FSC trap loss rate for $\\sp6$Li and $\\sp7$Li were found to be largest at smaller detunings and of comparable magnitude in $\\sp6$Li and $\\sp7$Li. The RE trap loss rate in $\\sp6$Li was seen to be roughly four times the RE trap loss rate in $\\sp7$Li. To understand better the dynamics of trap loss and magneto-optical traps in general, a sophisticated model of magneto-optical trap kinetics has been developed. This model has demonstrated that most critical factor determining the maximum velocity an atom may have and yet remained trapped is the initial atom's frame detuning, $\\Delta$ - k v, where $\\Delta$ is the trap laser detuning, k is the propagation vector of the trap beam most nearly anti-parallel to v, the atom's velocity. All else being equal, minimizing the magnitude of this quantity maximizes the velocity that a trap will retain. More detailed results of this model are also presented.

•Jan 1, 1994•0 citations

Interactions between laser-cooled lithium and sodium atoms in a magneto-optical trap (Invited Paper)

Laurentius Windholz

Storing and cooling simultaneously lithium and sodium atoms in a two-species magneto-optical trap, rate coefficients for collisions between these two atomic species were determined. The experiments were performed at different trap depths, thus for Li atoms the trap losses due to finestructure changing collisions could be distinguished from losses due to radiative escape. The rate coefficient for collisions between sodium and lithium atoms shows also a step when increasing the trap depth. The formation of cold heteronuclear molecules is claimed.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 22, 2005•0 citations

Trap loss collisions of6Li and7Li with23Na in a combined magneto-optical trap

Gerald Auböck, C Binder, L. Holler +5 more

We investigated heteronuclear inelastic cold collisions in a mixed-species Li–Na magneto-optical trap, where the Li trap loss from collisions with Na was measured. Experimental results for the rate coefficient β Na Li for the isotopes 6 Li as well as 7 Li as a function of the Li-MOT laser intensity are presented. Furthermore, we discuss some unique characteristics of cold collisions of Na and Li which arise from (1) the very small spin–orbit splitting of Li, (2) the very small C 6 coefficients of the Na(3 2 S) + Li(2 2 P) asymptotes and (3) the very small and inverted hyperfine structure of Li.

Journal of Physics B Atomic Molecular and Optical Physics•Sep 25, 2006•9 citations

Direct measurement of fine-structure collisional losses from a Cs magneto-optical trap

A. Fioretti, Jörg Helge Müller, Philippe Verkerk +3 more

Losses from a cesium magneto-optical trap induced by fine-structure changing collisions have been measured directly by counting of fluorescence photons emitted at the ${\mathrm{D}}_{1}$ resonance line, with the trap lasers operating on the ${\mathrm{D}}_{2}$ resonance line. The absolute value of the fine-structure loss rate coefficient has been measured and its dependence on the hyperfine state occupation has been explored. These results provide a fundamental test for the theoretical descriptions of excited-state trap losses.

Physical Review A•Jun 1, 1997•27 citations

Measurement of the collisional trap loss rate in magneto-optically trapped {sup 7}Li and {sup 6}Li

Nicholas W. M. Ritchie, Yangyang Xiao, E. Abraham +1 more

Collisions between ultra-cold (T << 1K) atoms confined in a magneto- optical trap (MOT) may result in the ejection of atoms from the trap. These collisional loss processes, which involve ground state/excited state collisions, fundamentally limit the density attainable in MOT traps. Although accurate calculations of collision rates between ultra-cold atoms require precise knowledge of the molecular potentials over a long range, the loss rate for Li was recently predicted to be significantly less than for the other alkali metals. Motivated by this result, we are measuring the collisional loss rate of Li in a vapor-cell MOT using a red-detuned laser beam to catalyze the collisions, similar to recent experiments using Rb and Cs. We will report our progress to measure the trap loss rate for {sup 6}Li and {sup 7}Li, which will be compared to investigate an isotopic dependence, as was recently observed for Rb.

Bulletin of the American Physical Society•May 1, 1993•0 citations

Trap loss in a two-species Na-Cs magneto-optical trap: Intramultiplet mixing in heteronuclear ultracold collisions

James P. Shaffer, Witek Chalupczak, N. P. Bigelow

We describe a comprehensive investigation of trap loss in a two-species Na-Cs magneto-optical trap. Observed losses, due to the interspecies interactions, are attributed to collisions in which a change in the fine-structure state of the Na partner causes the escape of atoms from the trap. Results are described in terms of the heteronuclear pair potentials and the interaction of the colliding pairs with the radiatively active environment.

Physical Review A•Nov 1, 1999•39 citations
We investigate collisional properties of lithium and cesium which are simultaneously confined in a combined magneto-optical trap. Trap-loss collisions between the two species are comprehensively studied. Different inelastic collision channels are identified, and inter-species rate coefficients as well as cross sections are determined. It is found that loss rates are independent of the optical excitation of Li, as a consequence of the repulsive Li∗^*∗-Cs interaction. Li and Cs loss by inelastic inter-species collisions can completely be attributed to processes involving optically excited cesium (fine-structure changing collisions and radiative escape). By lowering the trap depth for Li, an additional loss channel of Li is observed which results from ground-state Li-Cs collisions changing the hyperfine state of cesium.
Measurements of the trap loss rate in ultra-cold magneto-optically trapped sp6\\sp6sp6Li and sp7\\sp7sp7Li are presented and compared. Clear evidence is presented for two different trap loss mechanisms involving inelastic collisions between one ground state atom and one excited state atom. The fine-structure changing (FSC) mechanism, in which the excited state atom changes fine-structure level during a collision, is seen to dominate the rate at low trap laser intensities. However, as the intensity is increased, the trap becomes sufficiently deep to be able to contain the products of FSC collisions and this mechanism no longer contributes to trap loss. It is a unique aspect of Li that the energy imparted to an atom in a FSC collision is in a range that may be recaptured with experimentally attainable trap parameters. When the products of all FSC collisions remain trapped, only the radiative escape (RE) trap loss mechanism, due to the emission of a less energetic photon than the initial excitation photon, contributes to the trap loss rate. At small detunings, the rate of the RE trap loss mechanism is seen to be over two orders-of-magnitude smaller than the FSC rate. The FSC trap loss rate for sp6\\sp6sp6Li and sp7\\sp7sp7Li were found to be largest at smaller detunings and of comparable magnitude in sp6\\sp6sp6Li and sp7\\sp7sp7Li. The RE trap loss rate in sp6\\sp6sp6Li was seen to be roughly four times the RE trap loss rate in sp7\\sp7sp7Li. To understand better the dynamics of trap loss and magneto-optical traps in general, a sophisticated model of magneto-optical trap kinetics has been developed. This model has demonstrated that most critical factor determining the maximum velocity an atom may have and yet remained trapped is the initial atom's frame detuning, Delta\\DeltaDelta - k v, where Delta\\DeltaDelta is the trap laser detuning, k is the propagation vector of the trap beam most nearly anti-parallel to v, the atom's velocity. All else being equal, minimizing the magnitude of this quantity maximizes the velocity that a trap will retain. More detailed results of this model are also presented.
Storing and cooling simultaneously lithium and sodium atoms in a two-species magneto-optical trap, rate coefficients for collisions between these two atomic species were determined. The experiments were performed at different trap depths, thus for Li atoms the trap losses due to finestructure changing collisions could be distinguished from losses due to radiative escape. The rate coefficient for collisions between sodium and lithium atoms shows also a step when increasing the trap depth. The formation of cold heteronuclear molecules is claimed.
We investigated heteronuclear inelastic cold collisions in a mixed-species Li–Na magneto-optical trap, where the Li trap loss from collisions with Na was measured. Experimental results for the rate coefficient β Na Li for the isotopes 6 Li as well as 7 Li as a function of the Li-MOT laser intensity are presented. Furthermore, we discuss some unique characteristics of cold collisions of Na and Li which arise from (1) the very small spin–orbit splitting of Li, (2) the very small C 6 coefficients of the Na(3 2 S) + Li(2 2 P) asymptotes and (3) the very small and inverted hyperfine structure of Li.
Losses from a cesium magneto-optical trap induced by fine-structure changing collisions have been measured directly by counting of fluorescence photons emitted at the D1{\mathrm{D}}_{1}D1​ resonance line, with the trap lasers operating on the D2{\mathrm{D}}_{2}D2​ resonance line. The absolute value of the fine-structure loss rate coefficient has been measured and its dependence on the hyperfine state occupation has been explored. These results provide a fundamental test for the theoretical descriptions of excited-state trap losses.
Collisions between ultra-cold (T << 1K) atoms confined in a magneto- optical trap (MOT) may result in the ejection of atoms from the trap. These collisional loss processes, which involve ground state/excited state collisions, fundamentally limit the density attainable in MOT traps. Although accurate calculations of collision rates between ultra-cold atoms require precise knowledge of the molecular potentials over a long range, the loss rate for Li was recently predicted to be significantly less than for the other alkali metals. Motivated by this result, we are measuring the collisional loss rate of Li in a vapor-cell MOT using a red-detuned laser beam to catalyze the collisions, similar to recent experiments using Rb and Cs. We will report our progress to measure the trap loss rate for {sup 6}Li and {sup 7}Li, which will be compared to investigate an isotopic dependence, as was recently observed for Rb.