Journal of Physics B Atomic Molecular and Optical Physics

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

Jan Jette Blange, G Aben, H. Rudolph, Herman C. W. Beijerinck, H G M Heideman

Published Jun 28, 1997• 2 citations

Abstract

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.

DOI: 10.1088/0953-4075/30/12/009

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Journal of Physics B Atomic Molecular and Optical Physics

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

Jan Jette Blange, G Aben, H. Rudolph, Herman C. W. Beijerinck, H G M Heideman

Published Jun 28, 1997• 2 citations

Publisher

Abstract

DOI: 10.1088/0953-4075/30/12/009

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K

obey the relations

K(\frac{1}{2}, \frac{3}{2})=0

and

K(\frac{1}{2}, \frac{1}{2})=1.4K(\frac{3}{2}, \frac{3}{2})

, where the arguments indicate the initial magnetic substates

|{M}_{J}|

of the two colliding atoms.

We report cross-section measurements of the associative-ionization process, Na(3

{\mathit{p}}^{2}

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

)+Na(3

{\mathit{p}}^{2}

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

)\ensuremath{\rightarrow}

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

+e as a function of velocity, alignment, and orientation in the collision energy range from 300 to 5 K. Two independently tunable laser beams select narrow velocity classes of excited sodium in a well-collimated atomic beam. Circular and linear polarization of the excitation lasers permits alignment and orientation of the excited atoms in the two velocity classes. The excitation functions show pronounced differences reflecting different molecular pathways to the final product, and they bridge the energy range between conventional and ``cold'' collision dynamics.