Research Information System
PLASMA SOURCES SCIENCE & TECHNOLOGY, vol.8, no.3, pp.384-391, 1999 (SCI-Expanded)
Formation of O- ions in a pulsed discharge of O-2 was investigated in a Langmuir-probe-assisted photodetachment experiment. A large enhancement of negative ion formation was observed in the afterglow. Experimental results are consistent with O- formation via electron attachment to high Rydberg states of O-2 that survive into the afterglow. Such excited states can be produced by high-energy electron impact during the discharge. The lifetime of high-Rydberg molecules is estimated to be longer than 10 microseconds. The efficient production of O- ion by electron attachment to high-Rydberg O-2 molecules was further confirmed in a laser excitation experiment. The O- ions and O atoms produced via enhanced dissociative electron attachment to excited states of O-2 may be important for the chemical processes that occur in pulsed plasma remediation of contaminated air.