Light-induced drift of barium atoms.

Abstract

An observation of light-induced drift (LID) of atoms with an intermediate metastable level between the ground and excited resonance levels is reported. The drift of atoms of barium was investigated. Molecular nitrogen was used as a buffer gas. The 5d $^{1}$D metastable state of Ba atoms was quenched in collisions with ${\mathrm{N}}_{2}$ molecules. It has been deduced from the experimental results that the collision cross section of Ba atoms with ${\mathrm{N}}_{2}$ molecules is larger for Ba atoms in the ground state than in the 6p $^{1}$P excited state. The maximal LID velocity was about 250 cm/s.