Photo induced collisions with laser cooled He* atoms

Abstract

This paper presents an experimental investigation of cold collisions between metastable Helium atoms in an optical trap at 1mK. Penning (PI) and associative (AI) ionization reactions are distinguished using a mass spectrometer and studied under influence of near resonant laser light. Sensitive behavior of the ion rate is observed when the laser is tuned close to resonance. Experimental ?ndings are well described, on an absolute scale, by a semi-classical model we have developed for optical collisions and by a modi?ed Julienne-Vigu´e model.