1-Hexene was polymerized by rac-(dimethylsilyl)bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride catalyst and methylaluminoxane cocatalyst over the temperature range 0-100 degrees C. The polymerization rate, polymer molecular weight, and polymer microstructure (stereospecificity and regiospecificity) were studied as a function of the temperature and the concentrations of monomer, catalyst, and cocatalyst.