Alignment of multiplet components of atomic levels during collisions

V. N. Rebane, T. K. Rebane

A. G. Petrashen, V. N. Rebane, T. K. Rebane

The alignment of atomic states as the result of collisions with a beam of slow charged particles is investigated. The problem of the collisional reorientation of atomic moments is solved by numerical integration of the equations of the impact parameter method taking into account charge--quadrupole interaction. Calculations are made of the alignment of the /sup 2/P/sub 3//sub ///sub 2/ levels of alkali atoms populated by collisions with selective excitation of the /sup 2/P/sub 1//sub ///sub 2/ level. The linear polarization of light emitted by the /sup 2/P/sub 3//sub ///sub 2/ level attains some tens of percents and corresponds to the predominance of polarization in directions perpendicular to the beam. The efficiency of the resulting alignment depends on the volume density but not on the velocity of the beam of charged particles. Thus the slow drift of ions (and electrons) in a gas-discharge plasma can compete with alignment as the result of fluxes of charged particles. We shall formulate the sum rules for anisotropic collisional relaxation of atomic polarization moments. It follows from these that for the appearance of alignment in intramultiplet mixing under the action of anisotropic collisions we require a nonuniform population of multiplet levels that differs from the more » ratio of their statistical weights. « less

D. V. Skobelʹt︠s︡yn

E. Duman

Andrei V. Korol, Michael Yu. Kuchiev, Andrey V. Solov’yov

The authors demonstrate in this work that there is a peculiar source of low-frequency photon emission when a slow massive charged particle collides with an excited hydrogen atom. This radiation is generated by the rotating dipole moment of the hydrogen during the collision. The specific feature of the problem is in the appearance of the dipole moment of the excited hydrogen due to mixing of degenerated levels with different parity in the field of the projectile particle (linear Stark effect). The radiation associated with transitions between components of the Stark multiplet is also considered. Its contribution to the total radiation spectrum is shown to be important.

T Imagawa, T Yoshida, T. Shikama +1 more

In a temperature-controlled neon discharge cell under a magnetic field up to 7 T, a linearly polarized laser pulse has produced polarized neon atoms (atomic alignment) on the 2p 2 (in the Paschen notation) level from the 1s 3 level. The subsequent fluorescence to the 1s 2 level was observed with its polarized components being resolved. The disalignment rate coefficients of the 2p 2 atom due to neon atom collisions were determined at the temperature of 77 and 300 K. At each temperature, the rate coefficient shows no dependence on the magnetic field within the experimental accuracy.