title: A resistive pyrolytic radical source for gas-surface reaction studies.
abstract: We describe a thermal gas cracker designed to produce low fluxes of gas-phase radicals for use in radical-surface reaction studies. A resistively heated thin piece of highly oriented pyrolytic graphite is used as the pyrolysis filament, with the major advantage that this material remains inert at high temperatures. The instrument is built within an existing titanium sublimation pump, which simplifies construction and allows for self-pumping of the radical source. Thermal generation of Cl atoms from Cl(2) was chosen to test the effectiveness of the instrument. (35)Cl and (37)Cl were generated with a concomitant decrease in parent (70)Cl(2) and (72)Cl(2) species, as monitored by a residual gas analyzer. The cracking fraction of Cl(2) as a function of cell temperature is reported, with nearly full conversion achieved at high temperature.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: David Y
authors.initials: DY
authors.lastname: Lee
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Jobbins
authors.forename: S Alex
authors.initials: SA
authors.lastname: Kandel