Excitation of Zn+* levels in Penning and charge transfer reactions of He*(23S1) and He+ with zinc

Thermal, Penning and charge transfer reactions of He*(23S1) metastable atoms and He+ ions with zinc were studied in a flowing afterglow apparatus. The absolute values of the rate constants for excitation of the individual Zn+* levels have been measured. In Penning ionisation only 3.2 and 2.0% of the Zn+ ions are produced in the states which correspond to upper levels of the 747.9 and 589.4 nm laser lines respectively, while 90% of the ions are directly formed in the ground state. In charge transfer reactions, the fraction of the Zn+ ions excited in the four high lying 6p 2P, 5d 2D, 4f2F and 6s 2S states is about half of the product Zn+ ions, 45% being produced in 5d 2D levels. The total Penning ionisation and charge transfer rate constants were also measured. (author)