Collisional Properties of Cold Spin-Polarized Nitrogen Gas: Theory, Experiment, and Prospects as a Sympathetic Coolant for Trapped Atoms and Molecules
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Tscherbul, Timur V.
Klos, Jacek
Zygelman, Bernard
Pavlovic, Zoran
Hummon, Matthew T.
Tsikata, Edem
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https://doi.org/10.1103/PhysRevA.82.042718Metadata
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Tscherbul, Timur V., Jacek Klos, Alexander Dalgarno, Bernard Zygelman, Zoran Pavlovic, Matthew T. Hummon, Hsin-I Lu, Edem Tsikata, and John M. Doyle. 2010. Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules. Physical Review A 82(4): 042718.Abstract
We report a combined experimental and theoretical study of collision-induced dipolar relaxation in a cold spin-polarized gas of atomic nitrogen (N). We use buffer gas cooling to create trapped samples of \(^{14}\)N and \(^{15}\)N atoms with densities (5\(\pm\)2) × \(10^{12}\) \(cm^{-3}\) and measure their magnetic relaxation rates at milli-Kelvin temperatures. These measurements, together with rigorous quantum scattering calculations based on accurate \(ab\) \(initio\) interaction potentials for the \(^{7}\Sigma^{+}_{u}\) electronic state of \(N_{2}\) demonstrate that dipolar relaxation in N+N collisions occurs at a slow rate of ~\(10^{-13}\) \(cm^{3}\)/s over a wide range of temperatures (1 mK to 1 K) and magnetic fields (10 mT to 2 T). The calculated dipolar relaxation rates are insensitive to small variations of the interaction potential and to the magnitude of the spin-exchange interaction, enabling the accurate calibration of the measured N atom density. We find consistency between the calculated and experimentally determined rates. Our results suggest that N atoms are promising candidates for future experiments on sympathetic cooling of molecules.Other Sources
http://arxiv.org/abs/1007.0469Terms of Use
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