Accession Number : AD0660899

Title :   PHOTOIONIZATION OF ELECTRONICALLY EXCITED OXYGEN: RATE OF THE REACTION O2(A(1)DELTA-G)+O3 TO 2O2 +O,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LABS DIV

Personal Author(s) : McNeal,Robert J. ; Cook,Gilbert R.

Report Date : JUN 1967

Pagination or Media Count : 23

Abstract : The photoionization spectrum of discharged oxygen was obtained in the wavelength region 1040-1240A with an argon continuum light source and a 1-m Seya-Namioka scanning vacuum-ultraviolet monochromator in a discharge-flow experiment. Photoionization was detected only at wavelengths shorter than or equal to 1118.0A. The observed ion current is due to photoionization of metastable O2(a(1)Delta-g), and the effects on the ion current of adding O2, N2, and O3 to the flow stream after the discharge are reported. O2 and N2 do not reduce the photoionization current except by small percentages attributable to dilution effects, and with added O2, to a slight absorption of the incident light flux. O3, however, sharply reduces the ion current and is partially decomposed by the discharged gas. These effects are attributed to the reaction O2(a(1)Delta-g) + O3 to 2O2(X(3)Sigma-g(-)) + O((3)P). Measurements of the reduction in photoionization current as a function of added O3 pressure and reaction time were made, and the rate coefficient for this reaction at room temperature was found to be (2-3) x 10 to the -15th power cu. cm/molecule/sec. This is a lower value than has been estimated from discharge-flow experiments in which the metastable species responsible for ozone decomposition could not be identified. Possible reasons for the discrepancy are discussed. (Author)

Descriptors :   (*OXYGEN, *GAS IONIZATION), (*ULTRAVIOLET SPECTROSCOPY, OXYGEN), MOLECULAR ENERGY LEVELS, EXCITATION, PHOTOCHEMICAL REACTIONS, CONTINUOUS SPECTRA, ELECTRON TRANSITIONS, REACTION KINETICS, NITROGEN, OZONE, GAS DISCHARGES, ELECTRON TRANSITIONS

Subject Categories : Atmospheric Physics
      Radiation and Nuclear Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE