1. Laboratório
de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências
e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
2. Institut
Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex, France
3. Instituto
de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid, Spain
4. Centre
of Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
5. Centre
of Earth, Planetary, Space and Astronomy Research, Department of Physics
and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA, U.K.