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Homonuclear ionizing collisions of laser-cooled metastable helium atoms (14 pages)

John M. McNamara, R. J. W. Stas

Physical Review AJan 1, 20060 citations

Excitation of Metastable Helium Atoms to Rydberg States by STIRAP

Oleg Kritsun, Oleksii Boiko, Harold J. Metcalf

APSMay 1, 20041 citation

Collisional de-excitation of the metastableD-states of Ba+ by He, Ne, N2 and H2

A. Hermanni, Günther Werth

Zeitschrift für Physik D Atoms Molecules and ClustersDec 1, 198916 citations

The De-Excitation of Helium Metastable Atoms in Helium

E. H. S. Burhop

Proceedings of the Physical Society Section AMar 1, 195414 citations

Ionization and excitation of Rydberg states in collisions of fast metastable helium atoms with He, Ne and N2

Yu. A. Kudryavtsev, V. V. Petrunin

The cross sections for ionization and excitation into Rydberg states (n = 21-27) were determined for fast (accelerated to 3.9 keV) metastable helium atoms colliding with He, Ne, and N, .An analysis of the collisionally excited helium atoms in terms of their principal quantum number was carried out using for the ionization by an electric field a system capable of separation in accordance with n and was calibrated using signals from Rydberg states excited selectively by laser radiation.

Journal of Experimental and Theoretical PhysicsJan 1, 19910 citations

Coherence in Penning Ionization and First Kind Collisions: Volume Recombination of Ions/Electrons.

L. D. Schearer, W. F. Parks

A thermal energy beam of helium atoms in the metastable state is used to coherently excite ions of Sr, Ca, and Ba in a Penning collision. The anisotropic excited state distributions appears as Polarized line emission from the excited ions. The degree of ion alignment may be used to determine the populations of the quasi-molecular states of the ion-atom pair. The coherent emission is also utilized to obtain Hanle signals from which the radiative decay rate of the excited ion is determined. This is the first case in which coherence is produced in a collision process involving Penning ionization. The alignment of the Penning ions is an important new parameter in the description of these reactions. In an effort to extend such observations to molecular systems a nitrogen molecular metastable beam source was demonstrated. The use of metal vapor targets and the excitation rate of the excited states of Cd and Zn in energy transfer collisions with the N2(m) enable us to determine the vibrational distribution of the A 3Sigma state of N2 in the beam. Energy transfer cross sections and some Penning cross sections were measured in the beam system. (Author)A thermal energy beam of helium atoms in the metastable state is used to coherently excite ions of Sr, Ca, and Ba in a Penning collision. The anisotropic excited state distributions appears as Polarized line emission from the excited ions. The degree of ion alignment may be used to determine the populations of the quasi-molecular states of the ion-atom pair. The coherent emission is also utilized to obtain Hanle signals from which the radiative decay rate of the excited ion is determined. This is the first case in which coherence is produced in a collision process involving Penning ionization. The alignment of the Penning ions is an important new parameter in the description of these reactions. In an effort to extend such observations to molecular systems a nitrogen molecular metastable beam source was demonstrated. The use of metal vapor targets and the excitation rate of the excited states of Cd and Zn in energy transfer collisions with the N2(m) enable us to determine the vibrational distribution of the A 3Sigma state of N2 in the beam. Energy transfer cross sections and some Penning cross sections were measured in the beam system. (Author)

Dec 1, 19790 citations

Ionization and excitation into Rydberg states of fast metastable helium atoms in collisions with He, Ne, and N2

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Ionization and excitation into Rydberg states of fast metastable helium atoms in collisions with He, Ne, and N2

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