scholarly journals Comparison of optical response from DFT random phase approximation and a low-energy effective model: Strained phosphorene

2021 ◽  
Vol 104 (11) ◽  
Author(s):  
Mohammad Alidoust ◽  
Erlend E. Isachsen ◽  
Klaus Halterman ◽  
Jaakko Akola
2005 ◽  
Vol 3 (2) ◽  
pp. 141-149 ◽  
Author(s):  
M.R. Nikolic ◽  
Aleksandar Tancic

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.


2002 ◽  
Vol 2 (4) ◽  
pp. 183-188 ◽  
Author(s):  
Aleksandar Tancic ◽  
M.R. Nikolic

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.


2009 ◽  
Vol 18 (04) ◽  
pp. 975-985 ◽  
Author(s):  
J. KVASIL ◽  
P. VESELY ◽  
V. O. NESTERENKO ◽  
W. KLEINIG ◽  
P.-G. REINHARD ◽  
...  

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.


2017 ◽  
Vol 26 (04) ◽  
pp. 1750012 ◽  
Author(s):  
Tochtli Yepez-Martinez ◽  
Osvaldo Civitarese ◽  
Peter O. Hess

The SO(4) symmetry of a sector of the quantum chromodynamics (QCD) Hamiltonian was analyzed in a previous work. The numerical calculations were then restricted to a particle–hole (ph) space and the comparison with experimental data was reasonable in spite of the complexity of the QCD spectrum at low energy. Here on, we continue along this line of research and show our new results of the treatment of the QCD Hamiltonian in the SO(4) representation, including ground state correlations by means of the Random Phase Approximation (RPA). We are able to identify, within this model, states which may be associated to physical pseudo-scalar and vector mesons, like [Formula: see text], as well as the pion ([Formula: see text]).


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