Collision rates of optically oriented potassium atoms

Andrey N. Klyucharev, A. V. Lazarenko

Michael D. McGuire, E. Norval Fortson

In a new technique for studying electron collisions, the electrons are confined by electromagnetic fields and exposed to a known low density of atoms or molecules. Collisions rates are measured by electron diffusion in the trap. The use of spin-oriented atoms allows triplet and singlet contributions to be separated. Results of such studies are reported for room-temperature collisions of electrons with potassium atoms and with nitrogen molecules.

Christopher M. Wolfe

Victor A. Kartoshkin

Collisions between sodium and potassium atom in the conditions of optical orientation of potassium atoms are considered. Because of collisions, the spin exchange occurs between colliding atoms, which leads to a magnetic resonance frequency shift of Na atoms. Calculations reveal that the magnetic resonance frequency shift of Na atoms in the upper hyperfine state (F = 2) changes its sign from negative to positive upon an increase in the temperature in the absorption chamber from 300 to 500 K and passes through zero near temperature T ~ 450 K, while the frequency shift of the lower hyperfine state (F = 1) remains negative in the entire range of investigated temperatures. An analogous effect is observed for the first time in the case in which the main contribution to the magnetic resonance frequency shift comes from the spin exchange.

W. Berdowski, L. Krause

A modified Zeeman scanning method was used to excite selectively the magnetic substates of the $4^{2}P_{\frac{1}{2}}$ potassium atoms mixed with inert gases and placed in a strong magnetic field. The resulting potassium-inert-gas atomic collisions induced ${m}_{J}$ mixing in potassium, which manifested itself by the depolarization of the potassium resonance fluorescence. The polarization measurements yielded the following disorientation cross sections: K-He: 46 ${\mathrm{\AA{}}}^{2}$; K-Ne: 39 ${\mathrm{\AA{}}}^{2}$; K-A: 52 ${\mathrm{\AA{}}}^{2}$; K-Kr: 80 ${\mathrm{\AA{}}}^{2}$; K-Xe: 107 ${\mathrm{\AA{}}}^{2}$.

Eite Tiesinga, Paul S. Julienne, Xiaotian Wang +3 more