chloride amongst these triethyl aluminum triisobutyl aluminum ethylbutyl magnesium and triethyl aluminum are preferred the inventive catalyst may be used suitably used for a multi stage mode of polymerization involving different hydrogen concentrations monomer concentrations polymerization pressures and temperatures and other reaction parameters the invention will be described in more details by way of the following examples however it is to be understood that the invention is not intended to be limited to the specific embodiments the measurements for the physical properties of the polymers obtained in examples were conducted in accordance with the following methods melt flow rate mfr measured in accordance with condition no 4 in table 1 of jis k 7210 at 190 u00b0 c with load of 2 16 kg bulk density measured in accordance with jis k 6721 using a bulk density measurement device manufactured by kuramochi kagaku co ltd molecular weight distribution mw mn measured of a flow of 0 1 mil min at 135 u00b0 c by a gel permeation chromatography waters co model no 1500 gpc using an ortho dichlorobenzene gmh 6 by column toyo soda co a 200 cc three necked flask was charged with 20 ml refined toluene under nitrogen atmosphere and then with 1 mmol zr obu 4 and 8 mmol indene and heated to 90 u00b0 c the resulting solution was added with a toluene solution containing 8 mmol of triisobutylaluminum.