Berlin 2001 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

A: Atomphysik

A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)

A 12.37: Poster

Donnerstag, 5. April 2001, 12:30–15:00, AT3

Disalignment of excited neon atoms due to helium atom collisions in low temperature regime — •Masahiro Hasuo, Manabu Seo, Kouretsu Boku, Takayuki Shimamura, and Takeshi Fujimoto — Dept. of Engineering Physics and Mechanics, Faculty of Engineering, Graduate School at Kyoto University, Yoshidahommachi Sakyoku Kyotoshi Kyoto, Japan ZIP:606-8501

Relaxation of the angular momentum of uni-axially polarized (aligned) atoms is called disalignment. The disalignment process due to atom-atom collisions reflects the molecular potentials between the colliding atoms. We have observed the disalignment of excited neon atoms in the 2p⁵3p configuration (2p₂ and 2p₇: Paschen notation) in a helium-neon glow discharge at temperatures between 20 and 77K. At each temperature the disalignment rate is plotted as a function of the helium atom density; its slope gives the rate coefficient for helium atom collisions and the intercept is interpreted as due to disalignment by neon atom collisions and by radiation trapping. The disalignment rate coefficient due to helium atom collisions for both 2p₂ and 2p₇ atoms shows a more rapid decrease with the decrease in the temperature below 40K than the theoretical predictions. This finding suggests that the disalignment cross section is smaller than the theory in the energy range below 3 meV.