Accession Number : ADA320236

Title :   Laser Probing of Cross Sections for Ionization of Excited States and Molecular Dissociation by Electron Impact.

Descriptive Note : Final rept. 1 Aug 92-31 Jul 96

Corporate Author : CALIFORNIA INST OF TECH PASADENA DIV OF CHEMISTRY AND CHEMICAL ENGINEERING

Personal Author(s) : McKoy, Vincent ; Srivastava, Santosh

PDF Url : ADA320236

Report Date : JUL 1996

Pagination or Media Count : 15

Abstract : Cross sections for electron-impact ionization of atoms and molecules and for electron-impact dissociation of molecules play an important role in determining the properties of electrical discharges, of the ionosphere and aurora, and of the plasmas that are widely used in microelectronics fabrication. The data base of these electron collision cross sections is very fragmentary or non-existent. This research has addressed these needs through the following accomplishments: Development, and application of a novel method for the measurement of accurate values of ionization cross sections of metal atoms. The discovery that the values of the ionization potential of C60 determined by the electron-impact and photoionization methods differ considerably indicating that low-lying metastable states are involved in the process. This may very well be the case for many other large molecules. Development of a time-of-flight, mass spectrometer of special design required for this effort.

Descriptors :   *MOLECULAR STATES, *LASERS, *CROSS SECTIONS, *ELECTRIC DISCHARGES, *IONIZATION, *DISSOCIATION, DATA BASES, IONOSPHERE, METALS, PROBES, COMPUTATIONS, IMPACT, MICROPROCESSORS, COMPUTERS, MOLECULES, PROCESSING, PLASMAS(PHYSICS), EXCITATION, FABRICATION, PARALLEL PROCESSING, ATOMS, SEMICONDUCTORS, GASES, ELECTRONS, MICROELECTRONICS, LOW LEVEL, MASS SPECTROMETERS, AURORAE, PHOTOIONIZATION, PARALLEL ORIENTATION, ADAPTATION, METASTABLE STATE, PARTICLE COLLISIONS, IONIZATION POTENTIALS.

Subject Categories : Inorganic Chemistry
      Atmospheric Physics
      Physical Chemistry
      Electricity and Magnetism
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE