Accession Number : AD0653214

Title :   DETERMINATION OF PARTIAL PHOTOIONIZATION CROSS SECTIONS BY PHOTOELECTRON SPECTROSCOPY,

Corporate Author : ADELAIDE UNIV (AUSTRALIA) DEPT OF PHYSICS

Personal Author(s) : Blake,A. J. ; Carver,J. H.

Report Date : 1967

Pagination or Media Count : 27

Abstract : A photoelectron energy spectrometer was used to determine partial photoionization cross sections of molecular oxygen, nitrogen and water vapour for monochromatic incident radiation in the wavelength range 584 - 900A. For each gas, cross sections were determined for transitions to particular ionic states which were identified by measuring the corresponding photoelectron energy. For molecular oxygen, cross sections were determined for transitions to the X(2)Pi-g, (a(4)Pi-u + A(2)Pi-u) b(4) Sigma(-)g and (2)Sigma(-)g states of O2(+) and at incident wavelengths longer than 680A a process of fluorescent autoionization involving quasi-stable states of the neutral oxygen molecule was also observed. Molecular nitrogen cross sections corresponding to transitions to the X(2)Sigma(+)g, A(2)Pi-u and B(2)Sigma(+)u states of N2(+) were determined. For water vapour, cross sections corresponding to transitions to the (2)B1 and (2)A1 states of H2O(+) were observed in addition to processes of dissociative ionization. In all cases the measurements illustrate the competition between various modes of decay which are energetically possible for incident radiation of a given wavelength. (Author)

Descriptors :   (*GAS IONIZATION, PROBABILITY), (*PHOTOELECTRONS, SPECTROSCOPY), (*OXYGEN, IONIZATION), (*NITROGEN, IONIZATION), (*WATER VAPOR, IONIZATION), PHOTOCHEMICAL REACTIONS, SPECTROMETERS, MOLECULAR ENERGY LEVELS, ELECTRON TRANSITIONS, FLUORESCENCE, DISSOCIATION, RELAXATION TIME, PHOTOLYSIS, AUSTRALIA

Subject Categories : Atmospheric Physics
      Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE