Excitation and charge transfer in low-energy Na/sup +/-Ne collisions
This work presents a multifaceted experimental and theoretical study of collisions of Na/sup +/ ions in the energy range 0.2--12 keV with Ne atoms. Four different collision experiments are reported here. With one, doubly differential cross sections in scattering angle and energy loss were obtained by electrostatic analysis for direct collisions in the energy range 0.5--3.0 keV. With a second, energy-loss spectra for the neutral component of the scattered beam were obtained by time-of-flight techniques. With a third, energy spectra of electrons ejected by autoionization decays were obtained in the impact energy range 0.5--12 keV. Finally, in a fourth experiment, cross sections were obtained for some important Ne II transitions excited by collisions in the energy range 0.2--10 keV. The results of these four experiments are combined with results from previous investigations to give detailed information on the relative role of the various one- and two-electron excitation processes. The interpretation of the experimental findings is carried out within the quasimolecular framework and is based on the results of ab initio calculations for a variety of potential-energy curves of the (Na-Ne)/sup +/ quasimolecule. It is shown that the observed processes are induced by a succession of independent transition mechanisms, namely, (i) primary single and double excitation of Ne 2p electrons at curve crossings of the 4fsigma molecular orbital with empty sigma orbitals, (ii) sigma ..-->.. ..pi.. population transfer via rotational coupling, (iii) core rearrangement processes (L-vacancy sharing), and finally (iv) outer-electron (Rydberg) sharing. The estimation of the importance of the different mechanisms is made using simple models (Landau-Zener, Demkov-Meyerhof) and extrapolations of previous theoretical and experimental results on the isoelectronic Ne-Ne system. Special attention has been focused on the production of Ne (2p/sup 5/3p) triplet states.
- Research Organization:
- Institute of Physics, University of Aarhus, DK-8000 Aarhus, Denmark
- OSTI ID:
- 6284255
- Journal Information:
- Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 19:4; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOMIC IONS
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
KEV RANGE 01-10
LANDAU-ZENER FORMULA
MULTIPLETS
NEON
NONMETALS
RARE GASES
SODIUM IONS
TRIPLETS