Alignment of a Mg and Ca metastable beam produced by discharge

Abstract

Sources of excited atoms in a metastable state produced by a discharge are important tools for several experiments in atomic physics. The axis defined by the electron current breaks the spherical symmetry and as a result, the magnetic sublevel cross section can be different and the atomic beam aligned. It is presented theoretical results for the energy dependence of the magnetic sub-level integral cross section for the 3¹S → 3³P Mg transition and 4¹S → 4³P on Ca, They suggest a strong energy dependent alignment at energies where the excitation cross section is also large. Analysis indicates that this may also be true for other atoms. The spin-orbit interaction, neglected during the excitation, is included after the collision. It produces a time dependent density matrix evaluated using state multipole. Collision experiments with these aligned atomic beams may provide information which can not be obtained when the atomic state description is an isotropic density matrix.