scholarly journals Optical potential approach to the slow positron scattering from helium atom

2002 ◽  
Vol 2 (4) ◽  
pp. 183-188 ◽  
Author(s):  
Aleksandar Tancic ◽  
M.R. Nikolic
Keyword(s):  
Elastic Scattering ◽  
Random Phase Approximation ◽  
Optical Potential ◽  
Random Phase ◽  
Low Energy ◽  
Phase Approximation ◽  
Positron Scattering ◽  
Slow Positron ◽  
Experimental Values ◽  
Theoretical Results

We have extended our previous calculations to include the contribution of the random-phase approximation (RPA) (improved) optical potential to the low energy elastic scattering in the electron+He system. Our improved RPA calculations are shown to be in better agreement with the experimental values than other theoretical results.

scholarly journals Elastic scattering of low-energy positron by atom

2005 ◽  
Vol 3 (2) ◽  
pp. 141-149 ◽  
Author(s):  
M.R. Nikolic ◽  
Aleksandar Tancic
Keyword(s):  
Elastic Scattering ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Dyson Equation ◽  
Low Energy ◽  
Phase Approximation ◽  
Correlation Effects ◽  
Slow Positron ◽  
Theoretical Results

In this paper, we present our calculation for the elastic scattering of the slow positron from atoms. The calculation is performed for He, Ne, Xe and Kr. In the calculations we used Random phase approximation. By slowing Dyson equation we take into account the correlation effects. Our results are consistent with experimental and other theoretical results.

Elastic Scattering of Low Energy Positrons by Atoms

1961 ◽  
Vol 16 (5) ◽  
pp. 500-505 ◽  
Author(s):  
F. B. Malik
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Dominant Role ◽  
Low Energy ◽  
S Wave ◽  
Positron Scattering ◽  
Analytical Approximations ◽  
Scattering Cross Sections ◽  
Theoretical Results ◽  
Oxygen Fluorine

Elastic scattering cross sections of low energy positrons (0 to about 40 eV) by Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon and Argon atoms are calculated by variational methods. The scattering potentials are taken to be the analytical approximations of different HARTREE potentials. Only s-wave is included. Comparisons with the available experimental datas of positron scattering by He, Ne an reveal that either a considerable strong polarisation potential will be required to bring the theoretical results at par with experiments or the formation of virtual positronium play a dominant role for this kind of elastic scattering.

scholarly journals SKYRME-RANDOM-PHASE-APPROXIMATION DESCRIPTION OF E1 STRENGTH IN 92–100Mo

2009 ◽  
Vol 18 (04) ◽  
pp. 975-985 ◽  
Author(s):  
J. KVASIL ◽  
P. VESELY ◽  
V. O. NESTERENKO ◽  
W. KLEINIG ◽  
P.-G. REINHARD ◽  
...  
Keyword(s):  
Energy Region ◽  
Random Phase Approximation ◽  
Compensation Effect ◽  
Giant Resonance ◽  
Random Phase ◽  
Low Energy ◽  
The Self ◽  
Nuclear Deformation ◽  
Phase Approximation ◽  
Self Consistent

The isovector dipole E1 strength in 92,94,96,98,100 Mo is analyzed within the self-consistent separable random-phase approximation (SRPA) model with Skyrme forces SkT6, SkM*, SLy6, and SkI3. The special attention is paid to the low-energy region near the particle thresholds (4-12 MeV), which is important for understanding of astrophysical processes. We show that, due to a compensation effect, the influence of nuclear deformation on E1 strength below 10-12 MeV is quite modest. At the same time, in agreement with previous predictions, the deformation increases the strength at higher energy. At 4-8 MeV the strength is mainly determined by the tail of E1 giant resonance. The four Skyrme forces differ in description of the whole giant resonance but give rather similar results below 12 MeV.

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