A metallocene catalyst comprising a cationic metallocene characterized by the formula: (Cp')(Cp) MQL !+ AlR'4 !- wherein Cp' and Cp are each a cyclopentadienyl or a hydrocarbyl substituted cyclopentadienyl group and are the same or different, M is a Group 4, 5, or 6 metal, Q is a hydride, or a hydrocarbyl radical, each Q being the same or different, except only one Q is a hydride, L is 1 or