Many-body calculations of positron scattering and annihilation from noble-gas atoms

被引:99
作者
Dzuba, VA
Flambaum, VV
Gribakin, GF
King, WA
机构
[1] SMITHSONIAN OBSERV, ITAMP, CAMBRIDGE, MA 02138 USA
[2] HARVARD UNIV, CAMBRIDGE, MA 02138 USA
关键词
D O I
10.1088/0953-4075/29/14/024
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
We have applied many-body theory methods to study the interaction of low-energy positrons with noble-gas atoms. The positron-atom correlation potential includes explicitly the contribution from the target polarization by the positron and that from the virtual positronium (Ps) formation. It is demonstrated that the correlations and Ps formation (or tunnelling of electrons from the atom to the positron) create virtual levels in the positron-atom system. The existence of the virtual levels strongly influences the scattering and increases the positron annihilation rate by up to 400 times. The calculated elastic cross sections are in good agreement with experimental data The inclusion of virtual Ps formation greatly improves the agreement with experimental annihilation rates with respect to calculations taking only the polarization into account. Our calculations have highlighted the difference between the calculation of positron-atom scattering and the calculation of corresponding annihilation rates. The annihilation rate is very sensitive to the behaviour of the wavefunction at small positron-electron separations. A simple approximate formula based on the Sommerfeld factor is suggested to account for the effect of electron-positron Coulomb attraction on the annihilation rates.
引用
收藏
页码:3151 / 3175
页数:25
相关论文
共 58 条
[41]   GASEOUS REACTIONS INVOLVING POSITRONIUM [J].
MASSEY, HSW ;
MOHR, CBO .
PROCEEDINGS OF THE PHYSICAL SOCIETY OF LONDON SECTION A, 1954, 67 (416) :695-704
[42]   Positron scattering by potassium [J].
McAlinden, MT ;
Kernoghan, AA ;
Walters, HRJ .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1996, 29 (03) :555-569
[43]   CROSS-CHANNEL COUPLING IN POSITRON-ATOM SCATTERING [J].
MCALINDEN, MT ;
KERNOGHAN, AA ;
WALTERS, HRJ .
HYPERFINE INTERACTIONS, 1994, 89 (1-4) :161-194
[44]   POSITRON SCATTERING FROM NOBLE-GASES [J].
MCEACHRAN, RP ;
MORGAN, DL ;
RYMAN, AG ;
STAUFFER, AD .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1977, 10 (04) :663-677
[45]   POSITRON SCATTERING FROM KRYPTON AND XENON [J].
MCEACHRAN, RP ;
STAUFFER, AD ;
CAMPBELL, LEM .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1980, 13 (06) :1281-1292
[46]   POSITRON SCATTERING FROM ARGON [J].
MCEACHRAN, RP ;
RYMAN, AG ;
STAUFFER, AD .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1979, 12 (06) :1031-1041
[47]   CORRECTION [J].
MCEACHRAN, RP .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1978, 11 (05) :951-953
[48]   POSITRON SCATTERING FROM NEON [J].
MCEACHRAN, RP ;
RYMAN, AG ;
STAUFFER, AD .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1978, 11 (03) :551-561
[49]  
Migdal A. B., 1967, THEORY FINITE FERMI
[50]   CLOSE-COUPLING THEORY OF POSITRON HYDROGEN SCATTERING [J].
MITROY, J .
AUSTRALIAN JOURNAL OF PHYSICS, 1993, 46 (06) :751-771