Positron-molecule scattering at low and medium energies

1996 ◽  
Vol 74 (7-8) ◽  
pp. 420-425 ◽  
Author(s):  
A. S. Ghosh ◽  
T. Mukherjee
Keyword(s):  
Cross Sections ◽  
Laboratory Frame ◽  
Excitation Threshold ◽  
Rotational Excitation ◽  
Close Coupling ◽  
Intermediate Energies ◽  
Recent Developments ◽  
Molecule Scattering ◽  
Scattering Cross Sections ◽  
Threshold Energies

This review surveys the recent developments carried out by us on positron–molecule scattering at low and intermediate energies. The relative merits between the laboratory frame rotational close-coupling (rotational LFCC) and the adiabatic nuclei rotation models near the electronic and rotational excitation threshold energies are discussed. The importance of the use of the rotational LFCC model for polar molecules is also reviewed. The rovibrational LFCC and the adiabatic nuclei rovibration models are used to calculate the scattering cross sections for e+–H2 scattering. The results demonstrate the necessity of the inclusion of the vibrational motion dynamically in the theory.

scholarly journals Coherent and incoherent channels of neutrino-nucleus reactions

2020 ◽  
Vol 16 ◽  
pp. 75
Author(s):  
P. C. Divari ◽  
T. S. Kosmas
Keyword(s):  
Cross Sections ◽  
Neutral Current ◽  
Charged Current ◽  
Preliminary Results ◽  
Scattering Cross ◽  
Neutrino Detection ◽  
Intermediate Energies ◽  
Nucleus Scattering ◽  
Scattering Cross Sections

Inelastic neutrino-nucleus scattering cross sections at low and intermediate energies are investigated for currently interesting nuclei employed in neutrino-detection experiments. This is an extension to charged current processes of our previous QRPA calculations referred to neutral current neutrino/antineutrino-nucleus reactions. Our preliminary results for the reactions 56Fe(νe, e−)56Co and 40Ar(νe, e−)40K compare rather well with similar calculations obtained in the context of continuum RPA.

Close‐coupling scattering cross sections for Ar–O2 collisions at 97.0 meV

1987 ◽  
Vol 87 (10) ◽  
pp. 5687-5693 ◽  
Author(s):  
M. S. Bowers ◽  
M. Faubel ◽  
K. T. Tang
Keyword(s):  
Cross Sections ◽  
Close Coupling ◽  
Scattering Cross ◽  
Scattering Cross Sections

scholarly journals Positron - Hydrogen Scattering at Intermediate Energies

1996 ◽  
Vol 49 (5) ◽  
pp. 919 ◽  
Author(s):  
Jim Mitroy
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Maximum Energy ◽  
Reaction Cross ◽  
Impact Excitation ◽  
Total Reaction Cross Section ◽  
Positron Impact ◽  
Close Coupling ◽  
Formation Cross Section ◽  
Intermediate Energies

Calculations of positron–hydrogen scattering at intermediate energies up to a maximum energy of 10 Ryd are performed using the close coupling (CC) approach. A large L2 basis of positron–hydrogen channels (28 states) is supplemented by the Ps(1s), Ps(2s) and Ps(2p) channels. The inclusion of the positronium states in the CC expansion leads to a model which can describe most of the physics of the positron–hydrogen system with a reasonable degree of accuracy. In particular, the positronium formation cross section, the total reaction cross section and the ionisation cross section are all in agreement with experiment. The elastic scattering cross section and the cross sections for positron impact excitation of the H(2s) and H(2p) levels are also reported.

scholarly journals Excitation of the lowest autoionizing level of caesium atoms by positron impact

2021 ◽  
Vol 2 (1) ◽  
pp. 77-83
Author(s):  
A. W. Munywoki ◽  
J. Okumu ◽  
C. S Singh
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
High Energy ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Distorted Wave ◽  
Positron Impact ◽  
Intermediate Energies ◽  
Threshold Energies ◽  
Determining Factor

We have obtained differential and integral cross sections for the excitation of caesium atom to the lowest autoionizing level by positron impact using the distorted wave approximation. We have also done calculations for electron impact excitation of the same level using the same method and compared our present positron/electron impact results with the available theoretical positron/ electron impact results and experimental electron impact results. It is found that the present positron impact integral cross sections are higher than the cross sections of Pangantiwar and Srivastava at low and intermediate energies, but the results converge as the energy increases in the high energy range. The disagreement at near threshold energies is due to the different distortion potentials used in the two calculations. The charge on the projectile is also a determining factor in the shape of the scattering cross section curves.

INTERFERENCE OF DIFFRACTIVE, REFRACTIVE AND COULOMB EFFECTS IN LIGHT NUCLEUS–NUCLEUS ELASTIC SCATTERING CROSS-SECTIONS AT INTERMEDIATE ENERGIES

2003 ◽  
Vol 12 (06) ◽  
pp. 827-840 ◽  
Author(s):  
YU. A. BEREZHNOY ◽  
A. S. MOLEV
Keyword(s):  
Cross Sections ◽  
Light Nucleus ◽  
Structural Features ◽  
Fresnel Diffraction ◽  
Diffraction Scattering ◽  
Intermediate Energies ◽  
S Matrix ◽  
Coulomb Effects ◽  
Scattering Cross Sections ◽  
Rainbow Scattering

The patterns typical of Fraunhofer and Fresnel diffraction scattering and refraction (rainbow) scattering are discussed. We extract different interference contributions responsible for the characteristic structural features of the analyzed scattering patterns by means of the S-matrix approach.

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