Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Alkali-Alkali Differential Spin-Exchange Scattering. I

David E. Pritchard, Gary M. Carter, Frank Y. Chu, Daniel Kleppner

Published Nov 1, 1970• 25 citations
Publisher

Abstract

We present measurements of differential elastic cross sections for various alkali-alkali pairs, as well as the angular dependence of the probability of electron spin exchange in these collisions. The resolution is sufficient to reveal interference structure in the angular dependence of both quantities. We describe our apparatus, which polarizes one incident beam and analyzes the polarization of the scattered atoms, and discuss the measurement and data-reduction procedures. Results are presented in the range 0.1-0.2 eV for the systems Na-Cs, Na-Rb, Na-K, K-Cs, and K-Rb.

DOI
10.1103/physreva.2.1922

Related papers

Collisions of Spin-Polarized Alkali Na and Cs Atoms in the Ground State

Victor A. Kartoshkin

Abstract The paper considers collisions involving spin polarized alkali Na and Cs atoms in the ground state. The complex cross sections for spin exchange and the elastic scattering cross sections of the considered atoms are calculated in the energy range from 10–4 to 10–2 a.u.

Optics and Spectroscopy•Feb 1, 2024•0 citations

Interaction between spin polarized alkali atoms

Victor A. Kartoshkin

Collisions of alkali-metal atoms in the ground state with the electron spin S = 1/2 are accompanied by exchange of electron coordinates between colliding particles, which leads to polarization transfer between them (i.e., to the well-known phenomenon of spin exchange). In addition, along with the polarization transfer from one partner to another, the magnetic resonance lines of colliding atoms are broadened and shifted in spin-exchange collisions. In particular the last two processes depend on the complex spin-exchange cross section. The real part of the cross section determines the so-called "spin-exchange cross section," which is responsible for the broadening of magnetic resonance lines, while the imaginary part determines the shift cross section, which governs the frequency shift of magnetic resonance. In order to describe the spin-exchange process one have to know complex spin-exchange cross sections. Complex spin-exchange cross sections are calculated on the basis of the data on the singlet (X 1 Σ + ) and triplet (a 3 Σ + ) potentials describing the interaction alkali-metal atoms in the ground state. Collisions of alkali-metal atoms Cs, Rb, K, Na in the ground state are considered in the energy interval of 10 −4 −10 −2 au.

Journal of Physics Conference Series•Dec 1, 2018•0 citations

Spin exchange in elastice- O2 collisions

Fernando J. da Paixo, Marco A. P. Lima, Vincent McKoy

Recent experiments using polarized electron beams have shown that spin exchange effects for elastic collisions with ${\mathrm{O}}_{2}$ and NO are much smaller than for Na atoms. We report calculated spin-flip differential cross sections for elastic collisions of polarized electrons with ${\mathrm{O}}_{2}$ in agreement with experiment. In general, we can attribute the large variation of the spin-flip differential cross sections to resonances and interference effects. Such features arising from interference, however, may be washed out in the molecular case due to the average over orientations. Calculations with oriented ${\mathrm{O}}_{2}$ molecules show strong exchange effects as for Na.

Physical Review Letters•Mar 16, 1992•31 citations

Charge exchange collisions between alkaline-earth ions and alkali atoms

Ludo Vermeeren, Peter Lievens, Anita Buekenhoudt +1 more

The ratio of the charge exchange cross sections for Ba + (5d) and Ba + (6s) on Na, Rb and Cs, for Sr + (4d) and Sr + (5s) on Na and Rb, and for Ca + (3d) and Ca - (4s) on Na have been measured for ion impact energies between 0.5 keV and 30 keV. For the collisions with Na, absolute charge exchange cross section values are derived using data for the resonant process Na+Na + as a reference. The results are compared to theoretical near-resonance predictions. A method is proposed to study the polarization dependence of the neutralization cross sections for reactions involving ionic D states.

Journal of Physics B Atomic Molecular and Optical Physics•Mar 14, 1992•5 citations

Collisions of alkali-metal atoms Cs and Rb in the ground state. Spin exchange cross sections

Victor A. Kartoshkin

Collisions of alkali-metal atoms 133 Cs and 85 Rb in the ground state are considered in the energy interval of 10 –4 –10 –2 au. Complex cross sections of the spin exchange, which allow one to calculate the processes of polarization transfer and the relaxation times, as well as the magnetic resonance frequency shifts caused by spin exchange Cs–Rb collisions, are obtained.

Optics and Spectroscopy•Sep 1, 2016•6 citations

Alkali-Alkali Differential Spin-Exchange Scattering. II

David E. Pritchard, Frank Y. Chu

We analyze the data on differential spin-exchange scattering in collisions between alkali atoms which was presented in Paper I by Pritchard, Carter, Chu, and Kleppner. The data on the probability of exchange is analyzed to obtain the relative phase shift produced by the triplet and singlet potentials. A semiclassical impact approximation is developed and used to calculate this phase shift from theoretical calculations of the asymptotic behavior of the potentials. The results are consistent with the data only when the largest calculated value for the van der Waals potential is combined with the smallest calculated value of the difference potential. We have also analyzed the rainbow structure in the spin-summed differential cross section to obtain information about the depth and shape of the minimum in the triplet potentials in various alkali-alkali systems. Finally, we compare the result of our analysis with results from other experiments on alkali-alkali systems.

Physical Review A•Nov 1, 1970•32 citations
We present measurements of differential elastic cross sections for various alkali-alkali pairs, as well as the angular dependence of the probability of electron spin exchange in these collisions. The resolution is sufficient to reveal interference structure in the angular dependence of both quantities. We describe our apparatus, which polarizes one incident beam and analyzes the polarization of the scattered atoms, and discuss the measurement and data-reduction procedures. Results are presented in the range 0.1-0.2 eV for the systems Na-Cs, Na-Rb, Na-K, K-Cs, and K-Rb.
Collisions of alkali-metal atoms in the ground state with the electron spin S = 1/2 are accompanied by exchange of electron coordinates between colliding particles, which leads to polarization transfer between them (i.e., to the well-known phenomenon of spin exchange). In addition, along with the polarization transfer from one partner to another, the magnetic resonance lines of colliding atoms are broadened and shifted in spin-exchange collisions. In particular the last two processes depend on the complex spin-exchange cross section. The real part of the cross section determines the so-called "spin-exchange cross section," which is responsible for the broadening of magnetic resonance lines, while the imaginary part determines the shift cross section, which governs the frequency shift of magnetic resonance. In order to describe the spin-exchange process one have to know complex spin-exchange cross sections. Complex spin-exchange cross sections are calculated on the basis of the data on the singlet (X 1 Σ + ) and triplet (a 3 Σ + ) potentials describing the interaction alkali-metal atoms in the ground state. Collisions of alkali-metal atoms Cs, Rb, K, Na in the ground state are considered in the energy interval of 10 −4 −10 −2 au.
Recent experiments using polarized electron beams have shown that spin exchange effects for elastic collisions with O2{\mathrm{O}}_{2}O2​ and NO are much smaller than for Na atoms. We report calculated spin-flip differential cross sections for elastic collisions of polarized electrons with O2{\mathrm{O}}_{2}O2​ in agreement with experiment. In general, we can attribute the large variation of the spin-flip differential cross sections to resonances and interference effects. Such features arising from interference, however, may be washed out in the molecular case due to the average over orientations. Calculations with oriented O2{\mathrm{O}}_{2}O2​ molecules show strong exchange effects as for Na.
The ratio of the charge exchange cross sections for Ba + (5d) and Ba + (6s) on Na, Rb and Cs, for Sr + (4d) and Sr + (5s) on Na and Rb, and for Ca + (3d) and Ca - (4s) on Na have been measured for ion impact energies between 0.5 keV and 30 keV. For the collisions with Na, absolute charge exchange cross section values are derived using data for the resonant process Na+Na + as a reference. The results are compared to theoretical near-resonance predictions. A method is proposed to study the polarization dependence of the neutralization cross sections for reactions involving ionic D states.
We analyze the data on differential spin-exchange scattering in collisions between alkali atoms which was presented in Paper I by Pritchard, Carter, Chu, and Kleppner. The data on the probability of exchange is analyzed to obtain the relative phase shift produced by the triplet and singlet potentials. A semiclassical impact approximation is developed and used to calculate this phase shift from theoretical calculations of the asymptotic behavior of the potentials. The results are consistent with the data only when the largest calculated value for the van der Waals potential is combined with the smallest calculated value of the difference potential. We have also analyzed the rainbow structure in the spin-summed differential cross section to obtain information about the depth and shape of the minimum in the triplet potentials in various alkali-alkali systems. Finally, we compare the result of our analysis with results from other experiments on alkali-alkali systems.