Positronium quenching via collisions with triplet states of photomagnetic molecules

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1988

OSTI ID:5394769

Eom, C I

The study of Ps (Positronium) interactions with triplet states of photomagnetic molecules has been made with different concentrations of triplet state molecules in the gas phase as well as in the solid phase. In contrast to Brandt's results, the positron lifetime and Doppler line shape results in both gas and solid samples suggest that Ps spin conversion cross sections are not large enough to induce observable changes in the Ps decay parameters at concentrations of the photomagnetic molecules in the range {approximately}10{sup {minus}8} to {approximately}10{sup {minus}4}. A new rate-equation theory based on the population dynamics has been proposed to give better understanding of the non-linear effects, should they be present, in the ortho-positronium decay rates ({lambda}{sub o{minus}Ps}) at higher photon fluxes and at higher concentrations of the photomagnetic molecules. Ortho-positronium spin conversion cross section ({sigma}{sub o{minus}Ps}) for oxygen molecule is obtained, from {lambda}{sub o{minus}Ps} data, to be 1.07 {times} 10{sup {minus}19} cm{sup 2}, which is in good agreement with previous observations. The intensity of free positron component (I{sub f}) is expected not to vary with oxygen concentration if there are no channels for Ps oxidation and Ps-molecule compound formation. However, I{sub f} data show as much as {approximately}40% increase with oxygen concentration in ethane-oxygen mixtures implying that such processes as Ps oxidation or Ps-molecule compound formation are possible. These processes are energetically not possible between the gas molecules and Ps with thermal energies. The possibilities for these processes are discussed by considering the hot' (non thermal) Ps reactions and O{sub 2} molecules in the mixtures.

• Research Organization: Texas Univ., Arlington, TX (United States)
• OSTI ID: 5394769
• Country of Publication: United States
• Language: English

Related Subjects

664500* -- Special Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BOSONS
CHEMICAL REACTIONS
COLLISIONS
CROSS SECTIONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
FLUIDS
GASES
LEPTONS
LIFETIME
MASSLESS PARTICLES
MATTER
MOLECULES
NONLINEAR PROBLEMS
NONMETALS
OXIDATION
OXYGEN
PHOTONS
POSITRONIUM
POSITRONIUM COMPOUNDS
POSITRONS
QUENCHING
SOLIDS