The collision cross sections for excitation energy transfer in Rb*(5P 3/2) + K(4S 1/2) → Rb(5S 1/2) + K*(4P J ) processes

Abstract

inAbstract. The collisional excitation transfer for the processes Rb*(5P3/2)+K(4SI/2)~Rb(5Sm)+K*(4Pj), J = 1/2, 3/2, was investigated using two-photon laser excitation technique with a thermionic heat-pipe diode as a detector. The population densities of the K 4Pj levels induced by collisions with excited Rb atoms as well as those produced by direct laser excitation of the potassium atoms were probed through the measurement of the thermionic signals generated due to the ionization of the potassium atoms emerging from the K(4Pj) ~ K(7S1/2) excitation channel. The measurements of the thermionic signals in addition to the spectroscopic determination of the potassium number density yield the following values for the excitation transfer cross sections: a 1 (Rb 5 193/2 --~ K 4pro)=8 ~2 and o-2(Rb 5P3/z~K 4P3/2)= 11 ~2 The accuracy of the presented results is T-15%. The obtained results are compared to those for the opposite processes K* (4 Pj) + Rb (5 S~/2) --* K (4 S1/2) + Rb* (5 P3/2).

The collision cross sections for the fine-structure mixing of caesium 6P levels induced by collisions with potassium atoms

“…This method has been reported earlier [5,15]. The absorption measurements were performed with a single mode, frequency stabilized laser diode (Sharp LTO27MDO, 2 = 777 nm at 25 °C, maximal power: 7 roW).…”

“…The missing data for Li*-K system, are very hard to obtain experimentally due to the spectral interference of the Li resonance lines with the potassium B-X molecular band. However, the data can be calculated quite reliably applying a simple but justified model [1, 6].The experimental arrangement, not shown explicitly, was similar to that reported previously [5]. A very small amount of caesium was added to the distilled potassium metal contained in the middle of the stainless steal heatpipe with Pyrex glass windows.…”

Collisional excitation transfer between lithium isotopes

“…Good agreement between experimental and theoretical results has been achieved also for the noble gas induced fine structure transfer in group IIA ions [8, 9-1, and recently for energy pooling in sodium [5, t0, 11-1. A review of the literature reveals that there is in the case of excitation transfer processes involving alkali atoms in resonance states and similar or dissimilar ground state alkali atoms considerable disagreement between experimental values of different groups as well as between experiment and theory [6,12]. As a rule, the calculated cross sections, which take into account only the first term in the multipole expansion of the long-range interaction potential, are too small and higher order terms have to be taken into account [13,14].…”