The Scattering Equations for Charged Particles Colliding with Many Body Systems

1975 ◽  
Vol 53 (17) ◽  
pp. 1615-1623 ◽  
Author(s):  
T. D. Bui ◽  
A. D. Stauffer
Keyword(s):  
Cross Sections ◽  
Adiabatic Approximation ◽  
Perturbation Technique ◽  
Sodium Atom ◽  
Orbital Method ◽  
Many Body ◽  
First Order ◽  
Atom Scattering ◽  
Alkali Atoms ◽  
Many Body Systems

We have derived the total wave function of a many body system scattering by a charged particle by using a first order perturbation technique (the polarized orbital method). The derivation is based on an adiabatic approximation for the incoming particle. Particular cases of electrons colliding with the alkali atoms are shown. S, P, and D wave phase shifts and the total elastic cross sections for electron–sodium atom scattering are calculated using this method for the energy range 0 to 4 eV.

scholarly journals Close Coupling Theory of Positron Scattering from Alkali Atoms

1994 ◽  
Vol 47 (6) ◽  
pp. 721 ◽  
Author(s):  
Jim Mitroy ◽  
Kurunathan Ratnavelu
Keyword(s):  
Cross Sections ◽  
Alkali Atom ◽  
Coupling Theory ◽  
Positron Scattering ◽  
Close Coupling ◽  
Total Cross Sections ◽  
Hartree Fock ◽  
Atom Scattering ◽  
Alkali Atoms ◽  
Rearrangement Process

The close coupling equatious for positron-alkali atom scattering are written as a set of coupled momentum-space Lippmann-Schwinger equations. The alkali atom is represented by a frozen-core model based upon the Hartree-Fock approximation. The interaction between the positronium and the residual ion is modified by the inclusion of a core potential. Similarly, a core term is present in the interaction describing the rearrangement process. Close coupling calculations of positron scattering from sodium are performed in a model containing multiple sodium (3s, 3p, 4s, 3d, 4p) and positronium (Is, 2s, 2p) states. Cross sections are reported for an energy range from threshold to 50�eV; the total cross sections are in agreement with experimental data.

Computer calculations of slow electrons scattering by sodium atoms

1977 ◽  
Vol 55 (7-8) ◽  
pp. 742-746 ◽  
Author(s):  
T. D. Bui
Keyword(s):  
Cross Sections ◽  
Sodium Atom ◽  
Incident Electron ◽  
Not Given ◽  
Atom Scattering ◽  
Sodium Atoms ◽  
Variational Calculations ◽  
Computer Calculations ◽  
Explicit Formulae ◽  
Slow Electrons

This is an addendum to a previous paper (Bui and Stauffer, to be referred to as I). The explicit formulae which are not given in I for the case of electron–sodium atom scattering are given in this addendum. Tables of all appreciable partial waves with L ≤ 10 are presented for various values of the energy of the incident electron up to 4 eV. Results for the total elastic cross sections are compared with the most recent variational calculations of Sinfailam and Nesbet.

scholarly journals Experimental Test of Spontaneous Correlation and Anomalous Sensitivity in Finite Highly Excited Many-Body Systems

2003 ◽  
Vol 12 (03) ◽  
pp. 377-393 ◽  
Author(s):  
Qi Wang ◽  
Sergey Yu Kun ◽  
Wendong Tian ◽  
Songlin Li ◽  
Zhonghe Jiang ◽  
...  
Keyword(s):  
Cross Sections ◽  
Experimental Test ◽  
Heavy Ion ◽  
Quantum Systems ◽  
Slow Phase ◽  
Many Body ◽  
Ion Collisions ◽  
Excited Complex ◽  
Many Body Systems ◽  
Phase Randomization

We have tested recent suggestion of anomalous sensitivity in highly excited quantum many-body systems. Two independent measurements of cross sections for the 19 F + 93 Nb strongly dissipative heavy-ion collisions have been performed at incident energies from 102 to 108 MeV in steps of 250 keV. In the two measurements we used different, independently prepared, 93Nb target foils with nominally the same thickness. The data indicate statistically significant non-reproducibility of the energy oscillating yields in the two measurements. The observed non-reproducibility is consistent with recent theoretical arguments on spontaneous correlation, slow phase randomization and chaos in highly excited complex quantum systems.

scholarly journals A Fully Relativistic Approach to Photon Scattering and Photoionization of Alkali Atoms

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 42
Author(s):  
Adam Singor ◽  
Dmitry Fursa ◽  
Igor Bray ◽  
Robert McEachran
Keyword(s):  
Cross Sections ◽  
Relativistic Effects ◽  
Photoionization Cross Section ◽  
Sodium Potassium ◽  
R Matrix ◽  
Atom Scattering ◽  
Alkali Atoms ◽  
Relativistic Approach ◽  
Scattering Cross Sections ◽  
Good Agreement

A fully relativistic approach to calculating photoionization and photon-atom scattering cross sections for quasi one-electron atoms is presented. An extensive set of photoionization cross sections have been calculated for alkali atoms: lithium, sodium, potassium, rubidium and cesium. The importance of relativistic effects and core polarization on the depth and position of the Cooper minimum in the photoionization cross section is investigated. Good agreement was found with previous Dirac-based B-spline R-matrix calculations of Zatsarinny and Tayal and recent experimental results.

Annihilation of positrons in helium, neon, and argon

1970 ◽  
Vol 48 (11) ◽  
pp. 1288-1302 ◽  
Author(s):  
R. E. Montgomery ◽  
R. W. LaBahn
Keyword(s):  
Cross Sections ◽  
Orbital Method ◽  
Scattering Process ◽  
Electron Atom ◽  
Atom Scattering ◽  
Energy Behavior ◽  
The Cross ◽  
Helium Neon ◽  
Atom Collision ◽  
Good Agreement

The electric field dependences of the direct annihilation rates for positrons in helium, neon, and argon are calculated. This is done by using a systematic description of the scattering process. The momentum transfer and direct annihilation cross sections are calculated within the framework of the polarized-orbital method which has worked well for electron–atom scattering. The cross sections are then used in the appropriate diffusion equation to determine the experimentally observable annihilation rates appropriate to the exponential decay region of the spectrum. The resulting annihilation rates are found to be extremely sensitive to the low-energy behavior of the cross sections. Best agreement between calculated and experimental annihilation rates is obtained for helium where fairly rigorous calculations of the cross sections are available. Good agreement between theory and experiment for neon and argon is obtained only by making judicious choices for the components of the distortion included in the calculations. It is thus concluded that the positron–atom scattering process is considerably more sensitive to the details of the mutual distortion interaction than is observed in the corresponding electron–atom collision process.

Erweiterung der Neuen Tamm-Dancoff-Methode auf Phasen- übergänge in Vielteilchensystemen / Extension of the New Tamm-Dancoff Method to Phase Transitions in Many-Body Systems

1975 ◽  
Vol 30 (2) ◽  
pp. 142-157
Author(s):  
A. Friederich ◽  
W. Gerling ◽  
K. Bleuler
Keyword(s):  
Function Method ◽  
Many Body ◽  
Quasi Particle ◽  
First Order ◽  
Hartree Fock ◽  
Bogoliubov Theory ◽  
Lipkin Model ◽  
Exactly Solvable ◽  
Intermediate States ◽  
Many Body Systems

Abstract We extend the New Tamm-Dancoff method by introducing intermediate states. In this way we are able to treat with the Green's function method the effect of nearby levels in many-body systems. We formulate the η-and the ζ-function method with intermediate states. Aldready in first order, the ζ-function method yields a whole series of new approximations in addition to known theories such as the Hartree-Fock theory and the Hartree-Bogoliubov theory. As an example we study intensively "the Hartree-Fock theory with intermediate states". The ζ-function method which is based on the η-function method yields in first order in addition to RPA, quasi-particle RPA and other approximations "RPA with intermediate states". We apply the Hartree-Fock theory with intermediate states and RPA with intermediate states to the exactly solvable Lipkin model.

REGULAR STRUCTURE OF LOW-LYING STATES FOR ATOMIC NUCLEI UNDER RANDOM INTERACTIONS

2008 ◽  
Vol 17 (supp01) ◽  
pp. 304-317
Author(s):  
Y. M. ZHAO
Keyword(s):  
Ground State ◽  
Collective Motion ◽  
Regular Structure ◽  
Positive Parity ◽  
Many Body ◽  
Random Interactions ◽  
Atomic Nuclei ◽  
Many Body Systems

In this paper we review regularities of low-lying states for many-body systems, in particular, atomic nuclei, under random interactions. We shall discuss the famous problem of spin zero ground state dominance, positive parity dominance, collective motion, odd-even staggering, average energies, etc., in the presence of random interactions.

Sign in / Sign up

Export Citation Format

Share Document