Physical Review A

Determination of the absolute rate constant for associative ionization in crossed-beam collisions between Na 3P322 atoms

Regina E. Bonanno, Jacques Boulmer, J. Weiner

Published Aug 1, 1983• 45 citations

Abstract

We report the determination of the absolute rate constant of ${\mathrm{Na}}_{2}^{+}$ production by associative ionization collisions between crossed beams of Na $3^{2}P_{\frac{3}{2}}$ atoms. New measurement techniques greatly improve the accuracy of rate-constant determinations in crossed-beam experiments. We find the rate constant to be (1.8\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}11}$ ${\mathrm{cm}}^{3}$${\mathrm{sec}}^{\ensuremath{-}1}$. This value is appreciably larger than many of those previously reported.

DOI: 10.1103/physreva.28.604

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Cold collisions in an atomic beam

H. R. Thorsheim, Yanping Wang, J. Weiner

Physical Review AMar 1, 199025 citations

Associative ionization in collisions between Na(3 P3/2 ) and Cs(6 P3/2 )

C. Gabbanini, M. Biagini, Silvia Gozzini +2 more

Physical Review AMar 1, 19916 citations

Ultracold photoassociative ionization collisions in an atomic beam: Optical field intensity and polarization dependence of the rate constant

Chun-Cheng Tsao, Reginaldo de Jesus Napolitano, Yang Wang +1 more

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Spin-selected velocity dependence of the associative ionization cross section in Na(3p)+Na(3p) collisions over the collision energy range from 2.4 to 290 meV

M-X. Wang, J. Keller, Jacques Boulmer +1 more

Physical Review AJan 1, 198731 citations

Associative ionization in collisions between excited Na atoms in the and the states

Jan Jette Blange, G Aben, H. Rudolph +2 more

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Measurement of product rotational alignment in associative-ionization collisions between polarized Na(3p) atoms

M-X. Wang, Mattanjah S. de Vries, J. Weiner

Physical Review AJan 1, 198613 citations

Physical Review A

Determination of the absolute rate constant for associative ionization in crossed-beam collisions between Na 3P322 atoms

Regina E. Bonanno, Jacques Boulmer, J. Weiner

Published Aug 1, 1983• 45 citations

Publisher

Abstract

We report the determination of the absolute rate constant of

{\mathrm{Na}}_{2}^{+}

production by associative ionization collisions between crossed beams of Na

3^{2}P_{\frac{3}{2}}

atoms. New measurement techniques greatly improve the accuracy of rate-constant determinations in crossed-beam experiments. We find the rate constant to be (1.8\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}

{10}^{\ensuremath{-}11}

{\mathrm{cm}}^{3}$${\mathrm{sec}}^{\ensuremath{-}1}

. This value is appreciably larger than many of those previously reported.

DOI: 10.1103/physreva.28.604

Related papers

Cold collisions in an atomic beam

H. R. Thorsheim, Yanping Wang, J. Weiner

We report a measurement of the rate constant for associative ionization (AI) between excited Na(3p) atoms colliding within a single beam at a velocity of 11.9 ${\mathrm{msec}}^{\mathrm{\ensuremath{-}}1}$, corresponding to a temperature of 65 mK. The collisions take place in a narrow velocity class of excited atoms produced by crossing the collimated Na beam with a monomode dye laser at an angle of 45\ifmmode^\circ\else\textdegree\fi{}. Light polarized linearly in the collision plane yields an AI rate constant greater than that for circular polarization by a factor of 2. We find ${K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{lin}}}$ =(12.2\ifmmode\pm\else\textpm\fi{}4.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ and ${K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{cir}}}$ =(6.1\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$. The experimental arrangement also permits absolute calibration of earlier crossed-beam measurements of the excitation function (cross section versus velocity) at conventional thermal beam kinetic energies. Present results together with earlier work show that the cross-sectional temperature dependence is in qualitative accord with theory.We report a measurement of the rate constant for associative ionization (AI) between excited Na(3p) atoms colliding within a single beam at a velocity of 11.9 ${\mathrm{msec}}^{\mathrm{\ensuremath{-}}1}$, corresponding to a temperature of 65 mK. The collisions take place in a narrow velocity class of excited atoms produced by crossing the collimated Na beam with a monomode dye laser at an angle of 45\ifmmode^\circ\else\textdegree\fi{}. Light polarized linearly in the collision plane yields an AI rate constant greater than that for circular polarization by a factor of 2. We find ${K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{lin}}}$ =(12.2\ifmmode\pm\else\textpm\fi{}4.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ and ${K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{cir}}}$ =(6.1\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$. The experimental arrangement also permits absolute calibration of earlier crossed-beam measurements of the excitation function (cross section versus velocity) at conventional thermal beam kinetic energies. Present results together with earlier work show that the cross-sectional temperature dependence is in qualitative accord with theory.

Physical Review AMar 1, 199025 citations

Associative ionization in collisions between Na(3 P3/2 ) and Cs(6 P3/2 )

C. Gabbanini, M. Biagini, Silvia Gozzini +2 more

The results of an experiment on the associative ionization collision between sodium and cesium excited atoms are reported. The atoms are excited by two resonant cw lasers to the 3 ${\mathit{P}}_{3/2}$ and 6 ${\mathit{P}}_{3/2}$ levels, respectively, and the formation of the ${\mathrm{NaCs}}^{+}$ molecular ion is observed. The rate constant of such process has been measured relative to the known rate constant of sodium associative ionization and its value resulted in K=(5.4\ifmmode\pm\else\textpm\fi{}3.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.The results of an experiment on the associative ionization collision between sodium and cesium excited atoms are reported. The atoms are excited by two resonant cw lasers to the 3${\mathit{P}}_{3/2}$ and 6${\mathit{P}}_{3/2}$ levels, respectively, and the formation of the ${\mathrm{NaCs}}^{+}$ molecular ion is observed. The rate constant of such process has been measured relative to the known rate constant of sodium associative ionization and its value resulted in K=(5.4\ifmmode\pm\else\textpm\fi{}3.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.

Physical Review AMar 1, 19916 citations

Ultracold photoassociative ionization collisions in an atomic beam: Optical field intensity and polarization dependence of the rate constant

Chun-Cheng Tsao, Reginaldo de Jesus Napolitano, Yang Wang +1 more

We report here measurements of two-body photoassociative ionization collisions between sodium atoms within an ultranarrow velocity class selected from a well-collimated, thermal atomic beam. Doppler-shifted excitation of the Na(3s ${\mathrm{}}^{2}$ ${\mathit{S}}_{1/2}$ ;F=1)\ensuremath{\rightarrow}Na(5p ${\mathrm{}}^{2}$ ${\mathit{P}}_{3/2}$ ) transition at 285 nm by a single-mode laser defines the narrow velocity class that subsequently populates the F=2 hyperfine level of the Na ground state by optical pumping. Probe laser beam excitation tuned near the Na(3s ${\mathrm{}}^{2}$ ${\mathit{S}}_{1/2}$ ;F=2)\ensuremath{\rightarrow}Na(3p ${\mathrm{}}^{2}$ ${\mathit{P}}_{3/2}$ ;F=3) transition produced photoassociative ionization with an average collision energy ${\mathit{E}}_{\mathit{K}}$ corresponding to a temperature of 5.3 mK ( ${\mathit{E}}_{\mathit{K}}$ =3/2kT). We determine the rate constant for the process as a function of probe beam intensity and polarization.We report here measurements of two-body photoassociative ionization collisions between sodium atoms within an ultranarrow velocity class selected from a well-collimated, thermal atomic beam. Doppler-shifted excitation of the Na(3s${\mathrm{}}^{2}$${\mathit{S}}_{1/2}$;F=1)\ensuremath{\rightarrow}Na(5p${\mathrm{}}^{2}$${\mathit{P}}_{3/2}$) transition at 285 nm by a single-mode laser defines the narrow velocity class that subsequently populates the F=2 hyperfine level of the Na ground state by optical pumping. Probe laser beam excitation tuned near the Na(3s${\mathrm{}}^{2}$${\mathit{S}}_{1/2}$;F=2)\ensuremath{\rightarrow}Na(3p${\mathrm{}}^{2}$${\mathit{P}}_{3/2}$;F=3) transition produced photoassociative ionization with an average collision energy ${\mathit{E}}_{\mathit{K}}$ corresponding to a temperature of 5.3 mK (${\mathit{E}}_{\mathit{K}}$=3/2kT). We determine the rate constant for the process as a function of probe beam intensity and polarization.

Physical Review AJan 1, 199511 citations

Spin-selected velocity dependence of the associative ionization cross section in Na(3p)+Na(3p) collisions over the collision energy range from 2.4 to 290 meV

M-X. Wang, J. Keller, Jacques Boulmer +1 more

We report new results on the direct measurement of the associative ionization (AI) cross section in collisions between velocity-selected and spin-oriented Na(3p) atoms. Improvements in the Doppler-shift velocity-selection technique permit measurement over an energy range spanning more than two orders of magnitude from subthermal to suprathermal regions. Spin orientations, parallel and antiparallel, enable determination of the excitation function (velocity dependence of the AI cross section) for the separate singlet and triplet manifolds of ${\mathrm{Na}}_{2}$ states contributing to the AI process.We report new results on the direct measurement of the associative ionization (AI) cross section in collisions between velocity-selected and spin-oriented Na(3p) atoms. Improvements in the Doppler-shift velocity-selection technique permit measurement over an energy range spanning more than two orders of magnitude from subthermal to suprathermal regions. Spin orientations, parallel and antiparallel, enable determination of the excitation function (velocity dependence of the AI cross section) for the separate singlet and triplet manifolds of ${\mathrm{Na}}_{2}$ states contributing to the AI process.

Physical Review AJan 1, 198731 citations

Associative ionization in collisions between excited Na atoms in the and the states

Jan Jette Blange, G Aben, H. Rudolph +2 more

For the first time, associative ionization has been observed in an atomic beam of excited sodium atoms in both the and the state. Relative values for the partial cross sections were obtained specified according to the different magnetic substate combinations of the two fine-structure states. These were found to be comparable to those for associative ionization between two atoms. However, the effect of the excitation on the ion production rate was found to be considerable and to depend strongly on the relative polarizations of the laser beams producing the two populations due to the redistribution of the involved magnetic sublevels. The results indicate that the initial orientation of the electron spin S does not significantly influence the associative ionization reaction at the mean collision energy of 25 meV.For the first time, associative ionization has been observed in an atomic beam of excited sodium atoms in both the and the state. Relative values for the partial cross sections were obtained specified according to the different magnetic substate combinations of the two fine-structure states. These were found to be comparable to those for associative ionization between two atoms. However, the effect of the excitation on the ion production rate was found to be considerable and to depend strongly on the relative polarizations of the laser beams producing the two populations due to the redistribution of the involved magnetic sublevels. The results indicate that the initial orientation of the electron spin S does not significantly influence the associative ionization reaction at the mean collision energy of 25 meV.

Journal of Physics B Atomic Molecular and Optical PhysicsJun 28, 19972 citations

Measurement of product rotational alignment in associative-ionization collisions between polarized Na(3p) atoms

M-X. Wang, Mattanjah S. de Vries, J. Weiner

We have studied the effect of reactant Na(3p) polarization on the rotational angular momentum alignment of product ${\mathrm{Na}}_{2}$ ${\mathrm{}}^{+}$ ions arising from associative-ionization (AI) collisions. Our results show that sensitivity of the AI rate constant to initial atomic polarization persists even when all hyperfine states are populated with broadband (3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$) pulsed laser excitation of Na ${(\mathrm{}}^{2}$ ${P}_{3/2}$ ) and that the spatial distribution of product rotational angular momentum vectors is anisotropic. We discuss a qualitative description of the collision process consistent with our measurements which indicates that \ensuremath{\sigma}-orbital symmetry is preferred to \ensuremath{\pi}-orbital symmetry as the colliding partners approach.We have studied the effect of reactant Na(3p) polarization on the rotational angular momentum alignment of product ${\mathrm{Na}}_{2}$${\mathrm{}}^{+}$ ions arising from associative-ionization (AI) collisions. Our results show that sensitivity of the AI rate constant to initial atomic polarization persists even when all hyperfine states are populated with broadband (3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$) pulsed laser excitation of Na${(\mathrm{}}^{2}$${P}_{3/2}$) and that the spatial distribution of product rotational angular momentum vectors is anisotropic. We discuss a qualitative description of the collision process consistent with our measurements which indicates that \ensuremath{\sigma}-orbital symmetry is preferred to \ensuremath{\pi}-orbital symmetry as the colliding partners approach.

Physical Review AJan 1, 198613 citations

We report the determination of the absolute rate constant of

{\mathrm{Na}}_{2}^{+}

production by associative ionization collisions between crossed beams of Na

3^{2}P_{\frac{3}{2}}

{10}^{\ensuremath{-}11}

{\mathrm{cm}}^{3}$${\mathrm{sec}}^{\ensuremath{-}1}

. This value is appreciably larger than many of those previously reported.

{K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{lin}}}

=(12.2\ifmmode\pm\else\textpm\fi{}4.3)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$

{\mathrm{cm}}^{3}

${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ and

{K}_{65\mathrm{m}\mathrm{K}{}^{\mathrm{cir}}}

=(6.1\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$

{\mathrm{cm}}^{3}

${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$. The experimental arrangement also permits absolute calibration of earlier crossed-beam measurements of the excitation function (cross section versus velocity) at conventional thermal beam kinetic energies. Present results together with earlier work show that the cross-sectional temperature dependence is in qualitative accord with theory.

The results of an experiment on the associative ionization collision between sodium and cesium excited atoms are reported. The atoms are excited by two resonant cw lasers to the 3

{\mathit{P}}_{3/2}

and 6

{\mathit{P}}_{3/2}

levels, respectively, and the formation of the

{\mathrm{NaCs}}^{+}

molecular ion is observed. The rate constant of such process has been measured relative to the known rate constant of sodium associative ionization and its value resulted in K=(5.4\ifmmode\pm\else\textpm\fi{}3.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$

{\mathrm{cm}}^{3}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.

{\mathrm{}}^{2}

{\mathit{S}}_{1/2}

;F=1)\ensuremath{\rightarrow}Na(5p

{\mathrm{}}^{2}

{\mathit{P}}_{3/2}

) transition at 285 nm by a single-mode laser defines the narrow velocity class that subsequently populates the F=2 hyperfine level of the Na ground state by optical pumping. Probe laser beam excitation tuned near the Na(3s

{\mathrm{}}^{2}

{\mathit{S}}_{1/2}

;F=2)\ensuremath{\rightarrow}Na(3p

{\mathrm{}}^{2}

{\mathit{P}}_{3/2}

;F=3) transition produced photoassociative ionization with an average collision energy

{\mathit{E}}_{\mathit{K}}

corresponding to a temperature of 5.3 mK (

{\mathit{E}}_{\mathit{K}}

=3/2kT). We determine the rate constant for the process as a function of probe beam intensity and polarization.

{\mathrm{Na}}_{2}

states contributing to the AI process.

We have studied the effect of reactant Na(3p) polarization on the rotational angular momentum alignment of product

{\mathrm{Na}}_{2}

{\mathrm{}}^{+}

ions arising from associative-ionization (AI) collisions. Our results show that sensitivity of the AI rate constant to initial atomic polarization persists even when all hyperfine states are populated with broadband (3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$) pulsed laser excitation of Na

{(\mathrm{}}^{2}

{P}_{3/2}

) and that the spatial distribution of product rotational angular momentum vectors is anisotropic. We discuss a qualitative description of the collision process consistent with our measurements which indicates that \ensuremath{\sigma}-orbital symmetry is preferred to \ensuremath{\pi}-orbital symmetry as the colliding partners approach.