Antoine CHAR (2007), Deadline America

Quemener, Nelly

doi:10.4000/communication.2167

Cited by 3 publications

(4 citation statements)

References 3 publications

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“…A similarly low value can be inferred for the least bound singlet 1 Σ + g state in our experiment from the same mechanism [14]. This effect is absent for Li 2 +Na, Li 2 +Li 2 , and collisions involving heavier alkali molecules, because these all have a higher density of decay states in the exit channel [1,14,31]. The effect is also only present for the highest vibrational state, in which the atoms spend the longest time near the outer turning point of the van der Waals potential, where they do not have sufficient kinetic energy to transfer to a collision partner in a vibrational relaxation process.…”

supporting

confidence: 85%

“…The observed deviation from universality in Li 2 +Li collisions can be explained using a full close-coupling quantum calculation that predicts a two-body coefficient of 5 × 10 −11 cm 3 /s for Li 2 in the least bound triplet 3 Σ + u state, and can be interpreted as a depletion mechanism [31]. A similarly low value can be inferred for the least bound singlet 1 Σ + g state in our experiment from the same mechanism [14]. This effect is absent for Li 2 +Na, Li 2 +Li 2 , and collisions involving heavier alkali molecules, because these all have a higher density of decay states in the exit channel [1,14,31].…”

supporting

confidence: 59%

“…From a chemistry standpoint, it is thus more interesting to search for examples of collisions that deviate from universality. Such deviations should be more prominent in systems with low mass and consequently a low density of available decay states [14,15], making 6 Li 2 , consisting of the lightest alkali atoms, a uniquely suitable experimental system. We observe that two-body collisions of Li 2 in the highest vibrational state with free Li atoms deviates sharply from universality, as reflected in an exceptionally small two-body decay coefficient.…”

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confidence: 99%

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Deviation from Universality in Collisions of UltracoldLi26Molecules

et al. 2013

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Collisions of6 Li2 molecules with free 6 Li atoms reveal a striking deviation from universal predictions based on long-range van der Waals interactions. Li2 closed-channel molecules are formed in the highest vibrational state near a narrow Feshbach resonance, and decay via two-body collisions with Li2, Li, and Na. For Li2+Li2 and Li2+Na, the decay rates agree with the universal predictions of the quantum Langevin model. In contrast, the rate for Li2+Li is exceptionally small, with an upper bound ten times smaller than the universal prediction. [1,[3][4][5], such as controlling collisions through magnetic/electric field tuning to access scattering resonances or level crossings, understanding whether reactions can depend sharply on the specific quantum state of the collision partners or on the details of short-range inter-particle interactions, characterizing the outgoing states of reaction products, demonstrating coherent control of reaction cross sections, and more.There exists a simple, universal description for twobody inelastic collisions and chemical reactions of an ultracold molecule with another molecule or atom [6][7][8]. This quantum Langevin model assumes a large number of available exit channels in the short-range part of the interaction potential, leading to a unit probability of loss there, and leaving the decay rate dependent on only the long-range van der Waals interaction between collision partners. It has been validated in various experimental settings These universal collisions have a 100% probability of loss at short-range and therefore do not depend on details of the interaction potential there, such as scattering resonances or reactivity determined by matrix elements between quantum states. From a chemistry standpoint, it is thus more interesting to search for examples of collisions that deviate from universality. Such deviations should be more prominent in systems with low mass and consequently a low density of available decay states [14,15], making 6 Li 2 , consisting of the lightest alkali atoms, a uniquely suitable experimental system. We observe that two-body collisions of Li 2 in the highest vibrational state with free Li atoms deviates sharply from universality, as reflected in an exceptionally small two-body decay coefficient. In contrast, the rates for both Li 2 +Li 2 and Li 2 +Na collisions are universal. A recent experiment inferred the rate of Li 2 +Li decay from atomic three-body loss, but in a model-dependent way with uncertainty overlapping both our measurement and the universal prediction [16].To our knowledge this is the first experimental realization of collisions with ultracold molecules where loss is described by physics beyond universal long-range van der Waals interactions [17]. Earlier work by the Rice group reported a low decay rate for Li 2 +Li 2 collisions [18], many orders of magnitude smaller than the universal prediction. In contrast, our measurement demonstrates that this rate is universal, addressing a puzzle that has been prominent for the last decade.We sympa...

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supporting

confidence: 85%

supporting

confidence: 59%

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confidence: 99%

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Deviation from Universality in Collisions of UltracoldLi26Molecules

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“…The magnetic field generated on the S site by superconducting magnets of the IN20 instrument could only be measured after finishing the design phase of S . The magnetic shielding design was therefore based on simulations using the two complementary codes Comsol [31] and MAENTOUCH [32]. The latter code is a homemade program for solving magnetostatic problems using the boundary element method.…”

Section: Magnetic Shieldingmentioning

confidence: 99%

The STEREO experiment

et al. 2018

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A: The S experiment is a very short baseline reactor antineutrino experiment aiming at testing the hypothesis of light sterile neutrinos as an explanation of the deficit of the observed neutrino interaction rate with respect to the predicted rate, known as the Reactor Antineutrino Anomaly. The detector center is located 10 m away from the compact, highly 235 U enriched core of the research nuclear reactor of the Institut Laue Langevin in Grenoble, France. This paper describes the S site, the detector components and associated shielding designed to suppress the external sources of background which were characterized on site. It reports the performances in terms of detector response and energy reconstruction.

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