Longitudinal relaxation time of aligned atoms

William J. Mullin, Franck Laloë, Richards, Michael, G.

E Jacobson

Mercury atoms are excited in a weak gas discharge to the metastable 63P2 state, forming a longitudinal alignment, which is observed in the absorption of the linearly polarised green Hg line ( lambda =5461 AA). By a pulsed RF field, transverse components of the alignment are produced additionally, giving rise to modulated absorption. During the free precession the signals decay due to depolarising collisions with mercury atoms in the ground state. The cross sections for the destruction of the alignment have been determined to be sigma 0=(262.9+or-5.2) AA2 for the longitudinal component, sigma 1=(257.8+or-7.5) AA2 for the first transverse component (modulated with the Larmor frequency) and sigma 2=(273.1+or-9.0) AA2 for the second transverse component (modulated with twice the Larmor frequency). It is emphasised that these values refer to the alignment.

M. V. Balabas, M. I. Karuzin, Anatoly S. Pazgalev

We report the results of an experimental investigation of the longitudinal relaxation time T 1 of the electronic polarization of the ground state of potassium atoms in cells with an antirelaxation coating on the walls. Investigations were performed for a number of cells at temperature T =24°C. The maximum recorded relaxation times τ are 3.6, 4.3, and 5.2 s for cells with diameter D =50,75, and 100 nm, respectively. These are the longest longitudinal relaxation times ever recorded in coated cells. The transverse relaxation time was measured for these cells at the same temperature: T 2 =0.72,1.1, and 1.4 s, respectively.

Thad Gilbert Walker

V L Vaks, V. V. Mityugov

The physical background of the relation T2 = 2T1 between the transverse and longitudinal relaxation times in atomic and molecular spectroscopy is discussed.

Joachim Burgd orfer