Evidence of significant coupling effects between scattering channel in positron-atom scattering experiments

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:199561

Stein, T S ^[1]

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1. Wayne State Univ., Detroit, MI (United States)

In order to simplify calculations of approximate total and some partial cross sections for projectile-atom scattering, certain open scattering channels are sometimes neglected (e.g. positronium [Ps] formation in the case of positron-atom scattering). Recent measurements by the author`s group and corresponding calculations by others of total and partial cross sections for positrons scattered by atoms provide evidence that the neglect of such scattering channels in some cases can result in calculated total and partial cross sections which are very misleading, even in situations where the contribution of the neglected channel itself to the overall scattering process is not necessarily a dominant one, due to significant coupling effects between the various scattering channels. As an intriguing example of this, the neglect of Ps formation in recent four-state close-coupling approximation (CCA) calculations of total cross sections for positrons scattered by potassium atoms results in significantly higher total cross sections and qualitatively much different behavior below 10 eV than seven-state CCA calculations by the same group which include Ps formation in the n=1 and n=2 states. The latter (seven state CCA) calculations are consistent with total and Ps formation cross sections recently measured by this group.

• OSTI ID: 199561
• Report Number(s): CONF-941129--; CNN: Grant PHY90-21044
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
EV RANGE 01-10
EV RANGE 10-100
POSITRON COLLISIONS
POTASSIUM
SCATTERING
TOTAL CROSS SECTIONS