抄録
Measurement of negative ion mobilities is carried out in O2 at atmospheric pressure. This high pressure condition gives extremely low electric field intensity compared with the other swarm experiments. In this paper, we describe the results of experimental values of O2- mobility in O2 varying with the drift length from 1.5cm to 9.4cm. The experiments were performed from 0.007 to 4.5V/cm? Torr in reduced electric field intensity. Mobility of O2- against the reduced electric field intensity are almost agreed within 3.5cm in drift length. Obtained zero field mobility of O2- is 2.13cm2/V•s and this value agree with the values of other researchers. But if the drift length is longer than 3.5cm, the zero field mobility of O2- become small with increase the ion drift length. This fact suggests that O2- changes to another ion species by ion-molecule collisions during the flight through the drift space.
