Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 853-857 |
| Seitenumfang | 5 |
| Fachzeitschrift | SCIENCE |
| Jahrgang | 327 |
| Ausgabenummer | 5967 |
| Publikationsstatus | Veröffentlicht - 12 Feb. 2010 |
| Extern publiziert | Ja |
Abstract
How does a chemical reaction proceed at ultralow temperatures? Can simple quantum mechanical rules such as quantum statistics, single partial-wave scattering, and quantum threshold laws provide a clear understanding of the molecular reactivity under a vanishing collision energy? Starting with an optically trapped near-quantum-degenerate gas of polar 40K 87Rb molecules prepared in their absolute ground state, we report experimental evidence for exothermic atom-exchange chemical reactions. When these fermionic molecules were prepared in a single quantum state at a temperature of a few hundred nanokelvin, we observed p-wave-dominated quantum threshold collisions arising from tunneling through an angular momentum barrier followed by a short-range chemical reaction with a probability near unity. When these molecules were prepared in two different internal states or when molecules and atoms were brought together, the reaction rates were enhanced by a factor of 10 to 100 as a result of s-wave scattering, which does not have a centrifugal barrier. The measured rates agree with predicted universal loss rates related to the two-body van der Waals length.
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in: SCIENCE, Jahrgang 327, Nr. 5967, 12.02.2010, S. 853-857.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Quantum-State Controlled Chemical Reactions of Ultracold Potassium-Rubidium Molecules
AU - Ospelkaus, S.
AU - Ni, K. K.
AU - Wang, D.
AU - De Miranda, M. H.G.
AU - Neyenhuis, B.
AU - Quéméner, G.
AU - Julienne, P. S.
AU - Bohn, J. L.
AU - Jin, D. S.
AU - Ye, J.
PY - 2010/2/12
Y1 - 2010/2/12
N2 - How does a chemical reaction proceed at ultralow temperatures? Can simple quantum mechanical rules such as quantum statistics, single partial-wave scattering, and quantum threshold laws provide a clear understanding of the molecular reactivity under a vanishing collision energy? Starting with an optically trapped near-quantum-degenerate gas of polar 40K 87Rb molecules prepared in their absolute ground state, we report experimental evidence for exothermic atom-exchange chemical reactions. When these fermionic molecules were prepared in a single quantum state at a temperature of a few hundred nanokelvin, we observed p-wave-dominated quantum threshold collisions arising from tunneling through an angular momentum barrier followed by a short-range chemical reaction with a probability near unity. When these molecules were prepared in two different internal states or when molecules and atoms were brought together, the reaction rates were enhanced by a factor of 10 to 100 as a result of s-wave scattering, which does not have a centrifugal barrier. The measured rates agree with predicted universal loss rates related to the two-body van der Waals length.
AB - How does a chemical reaction proceed at ultralow temperatures? Can simple quantum mechanical rules such as quantum statistics, single partial-wave scattering, and quantum threshold laws provide a clear understanding of the molecular reactivity under a vanishing collision energy? Starting with an optically trapped near-quantum-degenerate gas of polar 40K 87Rb molecules prepared in their absolute ground state, we report experimental evidence for exothermic atom-exchange chemical reactions. When these fermionic molecules were prepared in a single quantum state at a temperature of a few hundred nanokelvin, we observed p-wave-dominated quantum threshold collisions arising from tunneling through an angular momentum barrier followed by a short-range chemical reaction with a probability near unity. When these molecules were prepared in two different internal states or when molecules and atoms were brought together, the reaction rates were enhanced by a factor of 10 to 100 as a result of s-wave scattering, which does not have a centrifugal barrier. The measured rates agree with predicted universal loss rates related to the two-body van der Waals length.
UR - http://www.scopus.com/inward/record.url?scp=76749131169&partnerID=8YFLogxK
U2 - 10.1126/science.1184121
DO - 10.1126/science.1184121
M3 - Article
AN - SCOPUS:76749131169
VL - 327
SP - 853
EP - 857
JO - SCIENCE
JF - SCIENCE
SN - 0036-8075
IS - 5967
ER -