Enhancement of direct positron annihilation due to temporal capture by an atom

被引：13

作者：

Yamanaka, N ^{[1
]}

Kino, Y

Takano, Y

Kudo, H

Ichimura, A

机构：

[1] RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan

[2] Tohoku Univ, Dept Chem, Sendai, Miyagi 9808578, Japan

[3] Inst Space & Astronaut Sci, Kanagawa 2298510, Japan

来源：

PHYSICAL REVIEW A | 2003年 / 67卷 / 05期

关键词：

D O I：

10.1103/PhysRevA.67.052712

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

We investigate direct positron annihilation during a collision in a gas; this is physically separable from indirect annihilation, i.e., via formation of positronium (Ps) and its decay. The cross section of direct annihilation is calculated from the evolution of a wave packet with a time width much shorter than the Ps lifetime, where the direct contribution is extracted through the time dependence of the survival probability. The cross section obtained for a hydrogen atom is found to be enhanced in energies around 10 eV well above the Ps formation threshold. This enhancement is shown to be due to temporal positron capture with electronic excitation in the atom.

引用

页数：4

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