[1] Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel
[2] Faculty of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
[3] Carmel Olefins Ltd., P.O.B. 1468, Haifa 31014, Israel
[4] Chimie de la Matiere Condensee, Universite Paris 6 - T54-E5, 4 Place Jussieu, 75252 Paris Cedex 05, France