HR: 0800h
AN: P11D-0803 [Abstracts]
TI: The synthesis and direct detection of O-atoms in water ice
AU: * Cooper, P D
EM: pcooper6@gmu.edu
AF: George Mason University, Department of Chemistry and Biochemistry, MS 3E2, 4400
University Dr, Fairfax, VA 22030, United States
AU: Moore, M H
EM: Marla.H.Moore@nasa.gov
AF: NASA Goddard Space Flight Center, Astrochemistry Laboratory, Code 691, 8800 Greenbelt
Rd, Greenbelt, MD 20771, United States
AU: Hudson, R L
EM: hudsonrl@eckerd.edu
AF: Eckerd College, Department of Chemistry, 4200 54th Avenue South, St. Petersburg, FL
33711, United States
AB:
The detection of molecular oxygen on the surfaces, and O-atoms in the tenuous atmospheres of icy outer solar
system bodies has resulted in a number of laboratory studies that have investigated how molecular oxygen is
formed in radiolyzed ices. Due to the weak band strengths of oxygen's vibronic and electronic transitions,
detection of O2 is often performed by a mass spectrometer as the O2 is sputtered, desorbed or sublimed
out of the ice.
We present a new in situ method for inferring O2 formation via a method in which isotopologues of ozone
are detected in experiments where water ice is doped with small quantities of 18O2. The detection of
ozone isotopologues containing 16O shows that 16O atoms are produced directly from the radiolysis of
water. Based upon our laboratory data, we provide a lower estimate for O2 formation in radiolyzed ices that is
in agreement with the estimated O2 abundance on Ganymede.
DE: 5410 Composition (1060, 3672)
DE: 5422 Ices
DE: 6221 Europa
DE: 6222 Ganymede
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting