Collision of highly excited atoms

R. F. Stebbings

Alexander A. Zembekov, E. E. Nikitin, Alexandre I. Reznikov

Борис М. Смирнов

The properties of highly excited atoms are examined. Methods for producing and detecting such atoms are analyzed. Various processes that involve atoms in Rydberg states are described, including transitions between high-lying excited states induced by collisions with electrons and atoms, quenching by electrons and atoms, ionization by collisions with electrons, atoms, and molecules, charge exchange with ions, and so on.

J. C. de Aquino Carvalho, Isabelle Maurin, H. Failache +2 more

We study the excitation redistribution from cesium $7\mathrm{P}_{1/2}$ or $7\mathrm{P}_{3/2}$ to neighboring energy levels by Black Body Radiation (BBR) and inter atomic collisions using pump-probe spectroscopy inside a vapor cell. At low vapor densities we measure redistribution of the initial, velocity-selected, atomic excitation by BBR. This preserves the selected atomic velocities allowing us to perform high resolution spectroscopy of the $\mathrm{6D\rightarrow 7F}$ transitions. This transfer mechanism could also be used to perform sub-Doppler spectroscopy of the cesium highly-excited $\mathrm{nG}$ levels. At high densities we observe interatomic collisions redistributing the excitation within the cesium $\mathrm{7P}$ fine and hyperfine structure. We show that $\mathrm{7P}$ redistribution involves state-changing collisions that preserve the initial selection of atomic velocities. These redistribution mechanisms can be of importance for experiments probing high lying excited states in dense alkali vapor.

J. Pedersen

Andrew J. Speck, C. H. Storry, Eric A. Hessels +1 more

Lasers are used to choose the binding energies of highly excited positronium atoms (Ps*) created via charge exchange collisions. The lasers directly excite cesium (Cs) atoms to highly excited states (Cs*). These large Cs*atoms have a large cross section for resonant charge exchange collisions with trapped positrons. Highly excited Ps* is formed with a binding energy that is determined by the initial laser excitation. These Ps* should have a large cross section for resonant charge exchange collisions with trapped antiprotons—suggesting a possible new way to produce cold antihydrogen.