Comment on "Entropy lowering in ion-atom collisions" (2 pages)

Piotr Garbaczewski

D. Ciampini, Marco Anderlini

Valentin N. Ostrovsky

The recent experimental result by Nguyen et al. [Phys. Rev. A 71, 062714 (2005)] on the ratio of cross sections for charge exchange processes ${\mathrm{Rb}}^{+}+\mathrm{Rb}(5s)\ensuremath{\rightarrow}\mathrm{Rb}(5p)+{\mathrm{Rb}}^{+}$ and ${\mathrm{Rb}}^{+}+\mathrm{Rb}(5p)\ensuremath{\rightarrow}\mathrm{Rb}(5s)+{\mathrm{Rb}}^{+}$ is quantitatively derived from simple considerations within the general framework of the quasimolecular theory. Contrary to the expectations, applicability of the Demkov model for charge exchange with small energy defect is not shattered.

F. W. Sohon

Michio Matsuzawa

It is shown that the author's previously proposed model based on the interaction between a Rydberg electron and a neutral describes thermal quasi-elastic collisions of high-Rydberg atoms with the neutrals reasonably. A recently proposed mechanism based on the interaction between an atomic-ion core and the neutral has been found not to give any appreciable contribution to the collision processes mentioned above.

William Band, James L Park