1. a Daresbury Laboratory, Daresbury, Warrington , Cheshire , WA4 4AD , UK
2. b Department of Physics , Uppsala University , Box 530, SE-751 21 , Uppsala , Sweden
3. c Department of Nuclear Spectroscopy Methods , Institute of Nuclear Physics, Moscow State University , Moscow , 119899 , Russian Federation
4. d Department of Chemistry , Heriot-Watt University , Riccarton, Edinburgh , EH14 4AS , UK
5. e Laboratory of Quantum Chemistry, Computer Centre , Irkutsk State University , 664003 , Irkutsk , Russian Federation
6. f Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 253, D-69120 , Heidelberg , Germany