Physical Review A

Collisions between cold ground-state Na atoms

Eite Tiesinga, S. J. M. Kuppens, BOUDEWIJN J. VERHAAR, Henk T. C. Stoof

Published May 1, 1991• 28 citations

Abstract

We study hyperfine transitions in collisions between cold ground-state $^{23}\mathrm{Na}$ atoms, which are of crucial importance for the decay of the atomic density in magnetic traps. For comparable densities we find the initial decay by exchange collisions to be roughly a factor of 10 more rapid than that in atomic hydrogen. The doubly polarized atomic gas that thus forms spontaneously in this initial process subsequently decays by dipolar relaxation with a rate that is about a factor of 5 larger than that in atomic hydrogen. The sensitivity of the calculated rate constants associated with uncertainties in the singlet and triplet potentials is discussed.

DOI: 10.1103/physreva.43.5188

Related papers

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

Timur V. Tscherbul, Jacek A. Kłos, A. Dalgarno +6 more

arXiv:1007.0469Physical Review AOct 26, 201014 citations

Spin-polarized deuterium in magnetic traps

J. M. V. A. Koelman, Henk T. C. Stoof, BOUDEWIJN J. VERHAAR +1 more

We have calculated the spin-exchange two-body rate constants associated with the population dynamics of the hyperfine levels of atomic deuterium as a function of magnetic field in the Boltzmann zero-temperature limit. Results indicate that a gas of low-field--seeking deuterium atoms trapped in a static magnetic field minimum decays rapidly into an ultrastable gas of doubly spin-polarized deuterium. We also discuss the temperature dependence of various effects.

Physical Review LettersAug 10, 198748 citations

Spin exchange and dipolar relaxation rates in atomic hydrogen: Lifetimes in magnetic traps

Ad Lagendijk, Isaac F. Silvera, BOUDEWIJN J. VERHAAR

We have rigorously calculated all the possible two-body rate constants associated with population dynamics of the hyperfine levels of atomic hydrogen as a function of magnetic field at T=0 K. These results are important in view of the recently suggested use of magnetic traps to obtain Bose-Einstein condensation.

Physical review. B, Condensed matterJan 1, 198668 citations

Complex cross sections of spin exchange in collisions of sodium and potassium atoms in the ground state

Victor A. Kartoshkin

Complex cross sections of the spin exchange are calculated for the first time for interacting Na and K atoms based on the data on the singlet (X 1Σ+) and triplet (a 3Σ+) potentials that describe the interaction of these alkali-metal atoms in the ground state. The obtained cross sections allow one to theoretically consider the polarization transfer processes and calculate the relaxation times and the magnetic resonance frequency shifts caused by Na-K spin-exchange collisions.

Optics and SpectroscopyNov 1, 201015 citations

Dipolar relaxation of cold sodium atoms in a magnetic field

Bernard Zygelman

A quantum mechanical close coupling theory of spin relaxation in the stretched hyperfine level of sodium is presented. We calculate the dipolar relaxation rate of magnetically trapped cold sodium atoms in the magnetic field. The influence of shape resonances and the anisotropy of the dipolar interaction on the collision dynamics are explored. We examine the sensitivity of the calculated cross sections on the choice of asymptotic atomic state basis.

arXiv:physics/0209052Sep 12, 20020 citations

Spin exchange during collisions of two sodium atoms

Victor A. Kartoshkin

Based on data on the singlet (X 1Σ+) and triplet (a 3Σ+) potentials describing the interaction of two Na atoms in the ground state, the complex cross sections of spin exchange for the system under investigation are calculated. The obtained cross sections allow one to determine relaxation times, as well as magnetic-resonance frequency shifts caused by spin-exchange Na-Na collisions.

Optics and SpectroscopyApr 1, 20146 citations

Physical Review A

Collisions between cold ground-state Na atoms

Eite Tiesinga, S. J. M. Kuppens, BOUDEWIJN J. VERHAAR, Henk T. C. Stoof

Published May 1, 1991• 28 citations

Publisher

Abstract

We study hyperfine transitions in collisions between cold ground-state

^{23}\mathrm{Na}

atoms, which are of crucial importance for the decay of the atomic density in magnetic traps. For comparable densities we find the initial decay by exchange collisions to be roughly a factor of 10 more rapid than that in atomic hydrogen. The doubly polarized atomic gas that thus forms spontaneously in this initial process subsequently decays by dipolar relaxation with a rate that is about a factor of 5 larger than that in atomic hydrogen. The sensitivity of the calculated rate constants associated with uncertainties in the singlet and triplet potentials is discussed.

DOI: 10.1103/physreva.43.5188

Related papers

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

Timur V. Tscherbul, Jacek A. Kłos, A. Dalgarno +6 more

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 $^{14}\mathrm{N}$ and $^{15}\mathrm{N}$ atoms with densities $(5\ifmmode\pm\else\textpm\fi{}2)\ifmmode\times\else\texttimes\fi{}{10}^{12} {\mathrm{cm}}^{\ensuremath{-}3}$ 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 ${}^{7}{\ensuremath{\Sigma}}_{u}^{+}$ electronic state of ${\mathrm{N}}_{2}$ demonstrate that dipolar relaxation in $\mathrm{N}+\mathrm{N}$ collisions occurs at a slow rate of $~{10}^{\ensuremath{-}13} {\mathrm{cm}}^{3}$/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.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 $^{14}\mathrm{N}$ and $^{15}\mathrm{N}$ atoms with densities $(5\ifmmode\pm\else\textpm\fi{}2)\ifmmode\times\else\texttimes\fi{}{10}^{12} {\mathrm{cm}}^{\ensuremath{-}3}$ 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 ${}^{7}{\ensuremath{\Sigma}}_{u}^{+}$ electronic state of ${\mathrm{N}}_{2}$ demonstrate that dipolar relaxation in $\mathrm{N}+\mathrm{N}$ collisions occurs at a slow rate of $~{10}^{\ensuremath{-}13} {\mathrm{cm}}^{3}$/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.

arXiv:1007.0469Physical Review AOct 26, 201014 citations

Spin-polarized deuterium in magnetic traps

J. M. V. A. Koelman, Henk T. C. Stoof, BOUDEWIJN J. VERHAAR +1 more

Physical Review LettersAug 10, 198748 citations

Spin exchange and dipolar relaxation rates in atomic hydrogen: Lifetimes in magnetic traps

Ad Lagendijk, Isaac F. Silvera, BOUDEWIJN J. VERHAAR

Physical review. B, Condensed matterJan 1, 198668 citations

Complex cross sections of spin exchange in collisions of sodium and potassium atoms in the ground state

Victor A. Kartoshkin

Optics and SpectroscopyNov 1, 201015 citations

Dipolar relaxation of cold sodium atoms in a magnetic field

Bernard Zygelman

arXiv:physics/0209052Sep 12, 20020 citations

Spin exchange during collisions of two sodium atoms

Victor A. Kartoshkin

Optics and SpectroscopyApr 1, 20146 citations

We study hyperfine transitions in collisions between cold ground-state

^{23}\mathrm{Na}

^{14}\mathrm{N}

and

^{15}\mathrm{N}

atoms with densities $(5\ifmmode\pm\else\textpm\fi{}2)\ifmmode\times\else\texttimes\fi{}{10}^{12} {\mathrm{cm}}^{\ensuremath{-}3}$ 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 ${}^{7}{\ensuremath{\Sigma}}_{u}^{+}$ electronic state of

{\mathrm{N}}_{2}

demonstrate that dipolar relaxation in

\mathrm{N}+\mathrm{N}

collisions occurs at a slow rate of $~{10}^{\ensuremath{-}13} {\mathrm{cm}}^{3}$/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.