Spin-polarized electron capture for the Na+[sup 3]He[sup 2+] system at a [sup 3]He[sup 2+] impact energy of 5. 33--9. 33 keV/amu
- Kobe Tokiwa Jr. College, Ohtani-cho 2-6-2, Nagata, Kobe 653 (Japan)
- Department of Chemistry, Niigata University, Igarashinino-machi 8050, Niigata 950-21 (Japan)
- The Spring-8 Project Team, Kamigori-cho, Hyogo 678-12 (Japan)
- Laboratory of Nuclear Studies, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka 565 (Japan)
- Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567 (Japan)
[sup 3]He[sup +] atomic polarizations following the spin-polarized electron capture process for the N[rvec a](3[ital s])+[sup 3]He[sup 2+] system were measured at [sup 3]He[sup 2+] impact energies from 5.33 to 9.33 keV/amu. The magnitude of the [sup 3]He[sup +] atomic polarizations was deduced from the [sup 3]He[sup +] nuclear polarization measured by means of beam-foil spectroscopy. The observed polarization transfer coefficient [ital P][sub [ital T]] defined by the ratio of the [sup 3]He[sup +] atomic polarization to the sodium one showed a pronounced reduction from unity, which was qualitatively explained by the prediction of a simple cascade photon decay model. Evidence for a further reduction of [ital P][sub [ital T]] from the above model and a possible impact energy dependence of [ital P][sub [ital T]] suggested an excessive depolarization due to the presence of the collision alignment parameter [ital A][sub 0][sup col] of [sup 3]He[sup +] formed by the electron capture process. In order to see this more closely, the observed [ital P][sub [ital T]]'s were examined theoretically using the semiclassical impact parameter method, in which an 18-state molecular expansion was employed, and atomic-type electron translation effects were rigorously taken into account. Ensuring that both the absolute values and the impact energy dependence of the observed capture cross sections were remarkably well reproduced by the calculations in which the states up to 4[ital f] in [sup 3]He[sup +] were introduced, it was demonstrated that the calculated results for [ital P][sub [ital T]] qualitatively reproduced not only the absolute values of the observed [ital P][sub [ital T]]'s but also their gentle decrease with increasing impact energy. Production of nuclear polarizations resulting from the polarized electron capture processes between multicharged heavy ions and alkaline-earth-metal atoms is an example of one use of the future project of universal polarized heavy-ion sources.
- OSTI ID:
- 7263544
- Journal Information:
- Physical Review A; (United States), Vol. 50:2; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HELIUM 3
ION-ATOM COLLISIONS
ELECTRON CAPTURE
SODIUM
ALPHA PARTICLES
KEV RANGE 10-100
NUCLEI
SPIN ORIENTATION
YIELDS
ALKALI METALS
ATOM COLLISIONS
CAPTURE
CHARGED PARTICLES
COLLISIONS
ELEMENTS
ENERGY RANGE
EVEN-ODD NUCLEI
HELIUM ISOTOPES
ION COLLISIONS
ISOTOPES
KEV RANGE
LIGHT NUCLEI
METALS
ORIENTATION
STABLE ISOTOPES
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)