ANNIHILATION OF POSITRONS IN ORGANIC LIQUIDS
Angular correlation measurements of the two photon radintion from annihilation of positrons in organic liquids were made to obtain momertum distributions for the annihilating positron-electron pairs. The liquids used were benzene, fluorobenzene, chlorobenzene, bromobenzene, iodobenzene, o-xylene, m-xylene, p-xylene, heptane, and heptane with 0.02, 0.06, and 0.67 mole% iodine in solution. One solid, hexamethylbenzene, was also used. The momentum distributions for benzene, fluorobenzene, the xylenes, and heptane showed evidence of two defirite componerts of momentum, the lower one probably arising from positronium formation. The remaining benzene derivatives did not exhibit two definite components, but showed a reduction in the fraction of annihiiations occurring with iow momentum as the size of the halide atom increases. A quantitative separation of the components of momentum in benzene was made to obtain the fraction of annihilations occurring with low momentum by two methods, comparison with hexamethylbenzene and comparison with a calculated distribution for the high momentum component. The calcuiated distribution assumed that the positron wave function was zero within a specified radius for each atom of the benzene molecule and unity outside this distance and that Slater wave functions described the outer shell electrons of the benzene atoms. A value of 0.20 for the fraction of annihilations occurring with the low momentum was obtained by both methods. Values for the fraction of annihilations occurring in the low momentum component and with iodine molecules were obtained for the heptane-iodine solutions. The results are best interpreted by the use of an annihilation or capture cross section for the iodine molecule. (Dissertation Abstr., 23: No. 5, Nov. 1962)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-009300
- OSTI ID:
- 4733079
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Formation of OH radicals from radical cations of some substituted benzenes in aqueous solutions at 80/sup 0/ C and at room temperature: effect of oxygen
Formation of H and D atoms in pyrolysis of benzene-d/sub 6/, chlorobenzene, bromobenzene, and iodobenzene behind shock waves