nitrogen atmosphere at room temperature the admixture was stirred at 45 u00b0 c for 2 hours the procedure for the preparation of catalyst component a 39 was followed except that silica alumina surface area 300 m 2 g pore volume 0 7 cc g had average particle size 50 u03bcm was used in place of silica a 300 cc three necked flask was charged with 150 ml refined toluene 15 4 g alet 2 cl 4 2 g zr opr 4 and 3 4 g cyclopentadiene in nitrogen atmosphere at room temperature the admixture was stirred at 45 u00b0 c for 2 hours a 300 cc three necked flask was charged with 50 ml refined toluene 5 84 g triethylaluminum 4 85 g biscyclopentadienyldimethylsilane and 3 5 g zr oet 4 in nitrogen atmosphere at room temperature the admixture was stirred at 45 u00b0 c for 2 hours a 300 cc three necked flask was charged with 150 ml refined toluene 5 84 g triethylaluminum 3 7 g biscyclopentadienylmethane and 4 2 g zr opr 4 in nitrogen atmosphere at room temperature the admixture was stirred at 45 u00b0 c for 2 hours the procedure for catalyst component a 39 was followed except that 15 ml toluene solution of trimethylaluminum concentration 1 mmol ml was used in place of methylalmoxane a 300 cc three necked flask was charged with 150 ml refined toluene 11 7 g triethylaluminum 13 4 g bisindenylethane and 3 9 g zr opr 4 cl in nitrogen atmosphere at room temperature the admixture was stirred at 45 u00b0 c for hours 3 g zirconium.