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

High-field measurement of the 129Xe−Rb spin-exchange rate due to binary collisions

Yuan‐Yu Jau, Nicholas N. Kuzma, W. Happer

Published Nov 15, 2002• 40 citations
Publisher

Abstract

We have measured the binary spin-exchange rate coefficient for collisions between Rb and ${}^{129}\mathrm{Xe}$ atoms at a magnetic field $B=9.4\mathrm{T}$ and in the temperature range $160<T<200\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.$ The longitudinal spin-relaxation rate ${1/T}_{1}$ of ${}^{129}\mathrm{Xe}$ is dominated by ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}$ binary collisions. We measured ${1/T}_{1}$ using the methods of conventional nuclear magnetic resonance, with no spin enhancement by optical pumping. At the high magnetic field and large gas pressures used in this work, the contribution of ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}$ molecules to the spin-exchange rate was less than 0.1% of the binary-collision rate. The Rb atomic number density [Rb] was measured directly from the large Faraday rotation of the polarization of near-resonant light passing through the sample cells. The rate coefficient is $\ensuremath{\kappa}{=d(1/T}_{1})/d[\mathrm{Rb}]=(1.75\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}{\mathrm{cm}}^{3}/\mathrm{s}.$

DOI
10.1103/physreva.66.052710

Related papers

Measurement of Xe129−Cs binary spin-exchange rate coefficient

Yuan‐Yu Jau, Nicholas N. Kuzma, W. Happer

We report the first measurement of the spin-exchange rate coefficient for binary collisions between Cs and $^{129}\mathrm{Xe}$ atoms in the temperature range $110<T<150\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ at a $9.4\text{\ensuremath{-}}\mathrm{T}$ magnetic field. Under these conditions, binary spin-exchange collisions dominate the longitudinal nuclear spin-relaxation rate $1∕{T}_{1}$ of $^{129}\mathrm{Xe}$ gas. We measured $1∕{T}_{1}$ of a thermally polarized Xe gas using the saturation-recovery of conventional nuclear magnetic resonance. We also directly measured the Cs atomic number density [Cs] by using Faraday rotation of the linear polarization of a probing laser beam passing through the sample. The measured rate coefficient is $\ensuremath{\kappa}(9.4\phantom{\rule{0.3em}{0ex}}\mathrm{T})=d(1∕{T}_{1})∕d[\mathrm{Cs}]=(2.81\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$, which is about a factor of 1.6 higher than the previously measured spin-exchange rate coefficient of $^{129}\mathrm{Xe}\text{\ensuremath{-}}\mathrm{Rb}$ binary collisions. Using a calculated magnetic decoupling factor, we extrapolate our result to zero magnetic field: $\ensuremath{\kappa}(0\phantom{\rule{0.3em}{0ex}}\mathrm{T})=(4.1\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$.

Physical Review A•Jun 7, 2004•24 citations

Magnetic decoupling of 129Xe−Rb and 129Xe−Cs binary spin exchange

Yuan‐Yu Jau, Nicholas N. Kuzma, W. Happer

We report calculations of the magnetic decoupling of the nuclear spin relaxation rate of ${}^{129}\mathrm{Xe}$ atoms caused by binary collisions with Rb or Cs atoms in a gas. A semiclassical approximation, using a classical path for the collision and treating the spin interactions quantum mechanically, gives results that differ by no more than 2% from calculations with the distorted-wave Born approximation. Both computational methods show that the relaxation rate decreases substantially for magnetic fields of a few tens of teslas. For ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb},$ where recent experimental measurements are available, the calculated rate coefficients at the experimental field of 9.4 T are about 80% of the calculated values at zero field. At 9.4 T, the calculated rate coefficient for ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}$ is about one-half of the experimentally observed value. This discrepancy is probably due to inaccuracies in the van der Waals and spin-dependent potentials used in the calculations.

Physical Review A•Feb 28, 2003•23 citations

Rapid 129Xe–Rb spin-exchange rate measurement by using an atomic magnetometer

Linlin Chen, Yuan Ren

We propose a fast and accurate method for 129 X e − R b spin-exchange rate determination based on an atomic magnetometer at low magnetic field and low pressure. The 129 X e − R b spin-exchange rate can be estimated via the product of the maximum transverse spin polarization of 129 X e nuclei and the corresponding Rabi frequency. The velocity-averaged binary spin-exchange cross section and the rate constant for spin-exchange in 129 X e − R b van der Waals complexes are measured to be ⟨ σ ν ⟩ S E = ( 1.26 ± 0.13 ) × 10 − 16 c m 3 / s and κ 4 H e = 1326 ± ( 47 ) s − 1 in 4 H e buffer gas, respectively. With respect to the method based on the longitudinal relaxation rate, the method presented in this work can greatly facilitate the measurement process, determining the spin-exchange rate in several minutes. Moreover, this method is more suitable for vapor cells with long longitudinal relaxation time.

Applied Optics•Apr 1, 2020•4 citations

Spin-polarization dependence of the Rb-Xe spin-exchange optical pumping process

Bowen Song, Yanhua Wang, Nan Zhao

We experimentally study the Rb-Xe spin-exchange optical pumping process. The dependence of the spin-exchange rate on the intensity of the pumping light is measured at different temperatures under low magnetic fields. We demonstrate that the spin-exchange rate will decrease as the Rb spin polarization increases, which agrees well with the theoretical prediction. In our measurement, three spin exchange and spin relaxation mechanisms, namely, the spin exchange rates between Rb and Xe atoms caused by van der Waals molecule (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{vdW}}$) and binary collision (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{bin}}$) processes, and the spin relaxation rate due to the wall collision of Xe atoms (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{w}}$), have comparable magnitudes. These rates are extracted separately from the measured data with different Rb spin polarization at various temperatures. Our work provides a comprehensive confirmation of the physical picture of the spin-exchange optical pumping process.

Physical Review A•Aug 17, 2021•20 citations

Theory of spin-exchange optical pumping of 3 He and 129 Xe

Stephan Appelt, Andrei Ben-Amar Baranga, Christopher Erickson +3 more

We present a comprehensive theory of nuclear spin polarization of ${}^{3}\mathrm{He}$ and ${}^{129}\mathrm{Xe}$ gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are (1) spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; (2) spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; (3) electron-nuclear spin-exchange collisions between alkali-metal atoms and ${}^{3}\mathrm{He}$ or ${}^{129}\mathrm{Xe}$ atoms; (4) spin interactions in van der Waals molecules consisting of a Xe atom bound to an alkali-metal atom; (5) optical pumping by laser photons; (6) spatial diffusion. The static magnetic field is assumed to be small enough that the nuclear spin of the alkali-metal atom is well coupled to the electron spin and the total spin is very nearly a good quantum number. Conditions appropriate for the production of large quantities of spin-polarized ${}^{3}\mathrm{He}$ or ${}^{129}\mathrm{Xe}$ gas are assumed, namely, atmospheres of gas pressure and nearly complete quenching of the optically excited alkali-metal atoms by collisions with ${\mathrm{N}}_{2}$ or ${\mathrm{H}}_{2}$ gas. Some of the more important results of this work are as follows: (1) Most of the pumping and relaxation processes are sudden with respect to the nuclear polarization. Consequently, the steady-state population distribution of alkali-metal atoms is well described by a spin temperature, whether the rate of spin-exchange collisions between alkali-metal atoms is large or small compared to the optical pumping rate or the collisional spin-relaxation rates. (2) The population distributions that characterize the response to sudden changes in the intensity of the pumping light are not described by a spin temperature, except in the limit of very rapid spin exchange. (3) Expressions given for the radio-frequency (rf) resonance linewidths and areas can be used to make reliable estimates of the local spin polarization of the alkali-metal atoms. (4) Diffusion effects for these high-pressure conditions are mainly limited to thin layers at the cell surface and at internal resonant surfaces generated by radio-frequency magnetic fields when the static magnetic field has substantial spatial inhomogeneities. The highly localized effects of diffusion at these surfaces are described with closed-form analytic functions instead of the spatial eigenmode expansions that are appropriate for lower-pressure cells.

Physical Review A•Aug 1, 1998•443 citations

A nuclear spin-based129Xe and131Xe using optical polarization

Binquan Zhou, Linlin Chen, Guanqun Lei +3 more

We present a design for a spin-exchange optical pumping system to produce large quantities of highly polarized 129Xe and 131Xe. Low xenon concentrations in the flowing gas mixture which allow the laser to maintain high Cs polarization. The large spin-exchange rate between Cs and Xe through the long-lived van der Waals molecules at low pressure, combined with a high flow rate, results in large production rates of hyperpolarized xenon. The fast rates make it possible to obtain large nuclear polarizations after several minutes of optical pumping with a laser.At high Xe pressures. According to the theory, the longitudinal spin-elaxation rate 1T1 of Xe in a high-pressure sample containing only Xe and Cs vapor has the simple form is the velocity averaged binary spin-exchange cross section, It is the relaxation rate due to wall collisions and perhaps magnetic field inhomogeneities. Our results complement earlier studies performed at 129Xe pressures of about 20 Torr and 131Xe pressures of about 20 Torr and N2 pressures of 600 Torr . This work is useful for predicting spin-exchange rates between polarized Cs atoms and Xe nuclei.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 8, 2015•0 citations
We have measured the binary spin-exchange rate coefficient for collisions between Rb and 129Xe{}^{129}\mathrm{Xe}129Xe atoms at a magnetic field B=9.4TB=9.4\mathrm{T}B=9.4T and in the temperature range 160<T<200\ifmmode∘\else\textdegree\fiC.160<T<200\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.160<T<200\ifmmode∘\else\textdegree\fiC. The longitudinal spin-relaxation rate 1/T1{1/T}_{1}1/T1​ of 129Xe{}^{129}\mathrm{Xe}129Xe is dominated by 129Xe\ensuremath−Rb{}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}129Xe\ensuremath−Rb binary collisions. We measured 1/T1{1/T}_{1}1/T1​ using the methods of conventional nuclear magnetic resonance, with no spin enhancement by optical pumping. At the high magnetic field and large gas pressures used in this work, the contribution of 129Xe\ensuremath−Rb{}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}129Xe\ensuremath−Rb molecules to the spin-exchange rate was less than 0.1% of the binary-collision rate. The Rb atomic number density [Rb] was measured directly from the large Faraday rotation of the polarization of near-resonant light passing through the sample cells. The rate coefficient is \ensuremathκ=d(1/T1)/d[Rb]=(1.75\ifmmode±\else\textpm\fi0.12)\ifmmode×\else\texttimes\fi10\ensuremath−16cm3/s.\ensuremath{\kappa}{=d(1/T}_{1})/d[\mathrm{Rb}]=(1.75\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}{\mathrm{cm}}^{3}/\mathrm{s}.\ensuremathκ=d(1/T1​)/d[Rb]=(1.75\ifmmode±\else\textpm\fi0.12)\ifmmode×\else\texttimes\fi10\ensuremath−16cm3/s.
We report the first measurement of the spin-exchange rate coefficient for binary collisions between Cs and 129Xe^{129}\mathrm{Xe}129Xe atoms in the temperature range $110<T<150\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ at a $9.4\text{\ensuremath{-}}\mathrm{T}$ magnetic field. Under these conditions, binary spin-exchange collisions dominate the longitudinal nuclear spin-relaxation rate 1∕T11∕{T}_{1}1∕T1​ of 129Xe^{129}\mathrm{Xe}129Xe gas. We measured 1∕T11∕{T}_{1}1∕T1​ of a thermally polarized Xe gas using the saturation-recovery of conventional nuclear magnetic resonance. We also directly measured the Cs atomic number density [Cs] by using Faraday rotation of the linear polarization of a probing laser beam passing through the sample. The measured rate coefficient is $\ensuremath{\kappa}(9.4\phantom{\rule{0.3em}{0ex}}\mathrm{T})=d(1∕{T}_{1})∕d[\mathrm{Cs}]=(2.81\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$, which is about a factor of 1.6 higher than the previously measured spin-exchange rate coefficient of $^{129}\mathrm{Xe}\text{\ensuremath{-}}\mathrm{Rb}$ binary collisions. Using a calculated magnetic decoupling factor, we extrapolate our result to zero magnetic field: $\ensuremath{\kappa}(0\phantom{\rule{0.3em}{0ex}}\mathrm{T})=(4.1\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$.
We report calculations of the magnetic decoupling of the nuclear spin relaxation rate of 129Xe{}^{129}\mathrm{Xe}129Xe atoms caused by binary collisions with Rb or Cs atoms in a gas. A semiclassical approximation, using a classical path for the collision and treating the spin interactions quantum mechanically, gives results that differ by no more than 2% from calculations with the distorted-wave Born approximation. Both computational methods show that the relaxation rate decreases substantially for magnetic fields of a few tens of teslas. For ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb},$ where recent experimental measurements are available, the calculated rate coefficients at the experimental field of 9.4 T are about 80% of the calculated values at zero field. At 9.4 T, the calculated rate coefficient for ${}^{129}\mathrm{Xe}\ensuremath{-}\mathrm{Rb}$ is about one-half of the experimentally observed value. This discrepancy is probably due to inaccuracies in the van der Waals and spin-dependent potentials used in the calculations.
We propose a fast and accurate method for 129 X e − R b spin-exchange rate determination based on an atomic magnetometer at low magnetic field and low pressure. The 129 X e − R b spin-exchange rate can be estimated via the product of the maximum transverse spin polarization of 129 X e nuclei and the corresponding Rabi frequency. The velocity-averaged binary spin-exchange cross section and the rate constant for spin-exchange in 129 X e − R b van der Waals complexes are measured to be ⟨ σ ν ⟩ S E = ( 1.26 ± 0.13 ) × 10 − 16 c m 3 / s and κ 4 H e = 1326 ± ( 47 ) s − 1 in 4 H e buffer gas, respectively. With respect to the method based on the longitudinal relaxation rate, the method presented in this work can greatly facilitate the measurement process, determining the spin-exchange rate in several minutes. Moreover, this method is more suitable for vapor cells with long longitudinal relaxation time.
We experimentally study the Rb-Xe spin-exchange optical pumping process. The dependence of the spin-exchange rate on the intensity of the pumping light is measured at different temperatures under low magnetic fields. We demonstrate that the spin-exchange rate will decrease as the Rb spin polarization increases, which agrees well with the theoretical prediction. In our measurement, three spin exchange and spin relaxation mechanisms, namely, the spin exchange rates between Rb and Xe atoms caused by van der Waals molecule (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{vdW}}$) and binary collision (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{bin}}$) processes, and the spin relaxation rate due to the wall collision of Xe atoms (${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{w}}$), have comparable magnitudes. These rates are extracted separately from the measured data with different Rb spin polarization at various temperatures. Our work provides a comprehensive confirmation of the physical picture of the spin-exchange optical pumping process.
We present a comprehensive theory of nuclear spin polarization of 3He{}^{3}\mathrm{He}3He and 129Xe{}^{129}\mathrm{Xe}129Xe gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are (1) spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; (2) spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; (3) electron-nuclear spin-exchange collisions between alkali-metal atoms and 3He{}^{3}\mathrm{He}3He or 129Xe{}^{129}\mathrm{Xe}129Xe atoms; (4) spin interactions in van der Waals molecules consisting of a Xe atom bound to an alkali-metal atom; (5) optical pumping by laser photons; (6) spatial diffusion. The static magnetic field is assumed to be small enough that the nuclear spin of the alkali-metal atom is well coupled to the electron spin and the total spin is very nearly a good quantum number. Conditions appropriate for the production of large quantities of spin-polarized 3He{}^{3}\mathrm{He}3He or 129Xe{}^{129}\mathrm{Xe}129Xe gas are assumed, namely, atmospheres of gas pressure and nearly complete quenching of the optically excited alkali-metal atoms by collisions with N2{\mathrm{N}}_{2}N2​ or H2{\mathrm{H}}_{2}H2​ gas. Some of the more important results of this work are as follows: (1) Most of the pumping and relaxation processes are sudden with respect to the nuclear polarization. Consequently, the steady-state population distribution of alkali-metal atoms is well described by a spin temperature, whether the rate of spin-exchange collisions between alkali-metal atoms is large or small compared to the optical pumping rate or the collisional spin-relaxation rates. (2) The population distributions that characterize the response to sudden changes in the intensity of the pumping light are not described by a spin temperature, except in the limit of very rapid spin exchange. (3) Expressions given for the radio-frequency (rf) resonance linewidths and areas can be used to make reliable estimates of the local spin polarization of the alkali-metal atoms. (4) Diffusion effects for these high-pressure conditions are mainly limited to thin layers at the cell surface and at internal resonant surfaces generated by radio-frequency magnetic fields when the static magnetic field has substantial spatial inhomogeneities. The highly localized effects of diffusion at these surfaces are described with closed-form analytic functions instead of the spatial eigenmode expansions that are appropriate for lower-pressure cells.
We present a design for a spin-exchange optical pumping system to produce large quantities of highly polarized 129Xe and 131Xe. Low xenon concentrations in the flowing gas mixture which allow the laser to maintain high Cs polarization. The large spin-exchange rate between Cs and Xe through the long-lived van der Waals molecules at low pressure, combined with a high flow rate, results in large production rates of hyperpolarized xenon. The fast rates make it possible to obtain large nuclear polarizations after several minutes of optical pumping with a laser.At high Xe pressures. According to the theory, the longitudinal spin-elaxation rate 1T1 of Xe in a high-pressure sample containing only Xe and Cs vapor has the simple form is the velocity averaged binary spin-exchange cross section, It is the relaxation rate due to wall collisions and perhaps magnetic field inhomogeneities. Our results complement earlier studies performed at 129Xe pressures of about 20 Torr and 131Xe pressures of about 20 Torr and N2 pressures of 600 Torr . This work is useful for predicting spin-exchange rates between polarized Cs atoms and Xe nuclei.