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Direct positron annihilation and positronium formation in thermal plasmas

Journal Article · · Astrophysical Journal; (USA)
DOI:https://doi.org/10.1086/167792· OSTI ID:5356248
 [1]
  1. California Univ., La Jolla (USA)

In the present evaluation of the rate of direct positron annihilation with electrons in the nonrelativistic limit, general analytic expressions are given for the radiative recombination of positrons to form positronium. Formulae are derived for the radiative capture to bound states of atomic hydrogen, and the connection between the two problems is demonstrated. Annihilation from excited states of positronium is considered, and it is estimated that 90 percent of the annihilations occur from the ground 1s state for both ortho and para positronium following radiative capture and cascade. A convenient form is given for the photodissociation cross section of positronium. 15 refs.

OSTI ID:
5356248
Journal Information:
Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 344; ISSN ASJOA; ISSN 0004-637X
Country of Publication:
United States
Language:
English