Experimental absolute electron impact ionization cross-sections of Cl2 -: art. no. 118

We measured absolute partial cross-sections for the formation of Cl-2(+), Cl-2(2+), Cl+ and Cl-2(+) ions following electron impact on molecular chlorine (Cl-2) from threshold to 900 eV using a time-of-flight mass spectrometer. The ion spectrum at all impact energies is dominated by the singly charged ions with maximum cross-section values of 4.6 x 10(-16) cm(2) for Cl-2(+) at 32 eV and 4.0 x 10(-16) cm(2) for Cl+ at 70 eV. The cross-sections for the formation of the doubly charged ions are more than one order of magnitude lower. Double ionization processes account for about 6% of the total ion yield at 70 eV. The absolute total ionization cross-section of Cl-2 was obtained as the sum of all measured partial ionization cross-sections. To the extent possible, a comparison of our results with other available measured and calculated data is made.