We demonstrate that the dissociative recombination of [Formula presented] with low-energy electrons depends on the rotational energy of the molecular ion such that highly excited ions have a larger rate coefficient than colder ones. Observations on an ion beam continuously interacting with electrons at low relative velocity indicate that excited rotational levels are preferentially depleted which, in competition with radiative heating due to blackbody radiation, provides an opportunity for controlling the rotational temperature of stored molecules.
Bibliographical noteFunding Information:
We thank J. Tennyson for helpful discussions. This work has been funded in part by the German Federal Minister for Education, Science, Research and Technology (BMBF) in the framework of the German-Israeli Pro?>ject Cooperation on Future-Oriented Topics (DIP), by the German Israel Foundation for Scientific Research (GIF) under Contract No. I-707-55.7/2001, and by the European Community within the Research Training Network “Electron Transfer Reactions.” H. B. P. acknowleges support from the European Community program IHP through a Marie Curie fellowship under Contract No. HPMF-CT-2002-01833.