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Universal reaction rates for ultracold molecular collisions

Paul S. Julienne, Zbigniew Idziaszek

Bulletin of the American Physical SocietyMay 27, 20100 citations

Cold atomic and molecular collisions: approaching the universal loss regime

Matthew D. Frye, Paul S. Julienne, Jeremy M. Hutson

We investigate the behaviour of single-channel theoretical models of cold and ultracold collisions that take account of inelastic and reactive processes using a single parameter to represent short-range loss. We present plots of the resulting energy-dependence of elastic and inelastic or reactive cross-sections over the full parameter space of loss parameters and short-range phase shifts. We then test the single-channel model by comparing it with the results of coupled-channel calculations of rotationally inelastic collisions between LiH molecules and Li atoms. We find that the range of cross-sections predicted by the single-channel model becomes increasingly accurate as the initial LiH rotational quantum number increases, with a corresponding increase in the number of open loss channels. The results suggest that coupled-channel calculations at very low energy (in the s-wave regime) could in some cases be used to estimate a loss parameter and then to predict the range of possible loss rates at higher energy, without the need for explicit coupled-channel calculations for higher partial waves.We investigate the behaviour of single-channel theoretical models of cold and ultracold collisions that take account of inelastic and reactive processes using a single parameter to represent short-range loss. We present plots of the resulting energy-dependence of elastic and inelastic or reactive cross-sections over the full parameter space of loss parameters and short-range phase shifts. We then test the single-channel model by comparing it with the results of coupled-channel calculations of rotationally inelastic collisions between LiH molecules and Li atoms. We find that the range of cross-sections predicted by the single-channel model becomes increasingly accurate as the initial LiH rotational quantum number increases, with a corresponding increase in the number of open loss channels. The results suggest that coupled-channel calculations at very low energy (in the s-wave regime) could in some cases be used to estimate a loss parameter and then to predict the range of possible loss rates at higher energy, without the need for explicit coupled-channel calculations for higher partial waves.

arXiv:1412.5114New Journal of PhysicsApr 27, 201534 citations

Reactive collisions of trapped anions with ultracold atoms

Johannes Deiglmayr, A. Göritz, Th. Best +2 more

We present a scheme to embed molecular anions in a gas of ultracold rubidium atoms as a route towards the preparation of cold molecular ions by collisional cooling with ultracold atoms. Associative detachment as an important loss process in collisions between OH${}^{\ensuremath{-}}$ molecules and rubidium atoms is studied. The density distribution of trapped negative ions in the multipole radio frequency trap is measured by photodetachment tomography, which allows us to derive absolute rate coefficients for the process. We define a regime where translational and internal cooling of molecular ions embedded into the ultracold atomic cloud can be achieved.We present a scheme to embed molecular anions in a gas of ultracold rubidium atoms as a route towards the preparation of cold molecular ions by collisional cooling with ultracold atoms. Associative detachment as an important loss process in collisions between OH${}^{\ensuremath{-}}$ molecules and rubidium atoms is studied. The density distribution of trapped negative ions in the multipole radio frequency trap is measured by photodetachment tomography, which allows us to derive absolute rate coefficients for the process. We define a regime where translational and internal cooling of molecular ions embedded into the ultracold atomic cloud can be achieved.

arXiv:1211.2436Physical Review AOct 31, 201258 citations

Simple models for ultracold molecular collisions

Paul S. Julienne

Bulletin of the American Physical SocietyMar 17, 20100 citations

Elastic rate coefficients for Li+H2 collisions in the calibration of a cold-atom vacuum standard

Constantinos Makrides, Daniel S. Barker, James A. Fedchak +3 more

A coupled-channel calculation is carried out to compute rate coefficients for elastic collisions of room-temperature molecular hydrogen with ultracold lithium atoms. The results are relevant for the calibration of a planned cold-atom vacuum standard device that utilizes the rate of collisional loss of trapped atoms to measure background-gas pressures in the UHV and XHV regimes.

Physical Review AApr 29, 201929 citations

Ultracold Molecular Collisions

Jesús Pérez‐Ríos

Springer eBooksJan 1, 20200 citations

Approaching the universal loss regime in cold and ultracold molecular collisions

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