Alignment of atomic states by collisions with slow charged particles
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
Optics and Spectroscopy•Aug 1, 1984•0 citations