The production of O- and O-2(-) by dissociative electron attachment to ozon
e has been studied between about 0 and 10 eV with a high resolution crossed
beam apparatus recently developed in the Innsbruck laboratory. A previousl
y unobserved sharp structure is observed in the formation of O- ions at zer
o incident energy. This large additional cross section peak has important c
onsequences for the role of ozone in anion formation processes in the terre
strial ionosphere.