scholarly journals Scattering and Its Applications to Various Atomic Processes: Elastic Scattering, Resonances, Photoabsorption, Rydberg States, and Opacity of the Atmosphere of the Sun and Stellar Objects

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 78
Author(s):  
Anand K. Bhatia
Keyword(s):  
Elastic Scattering ◽  
Long Range ◽  
Short Range ◽  
Bound States ◽  
Rydberg States ◽  
Stellar Atmospheres ◽  
Electron Systems ◽  
Short Range Correlations ◽  
Hybrid Theory ◽  
Scattering Resonances

A scattering process can be a natural process or a process carried out in a laboratory. The scattering of particles from targets has resulted in important discoveries in physics. We discuss various scattering theories of electrons and positrons and their applications to elastic scattering, resonances, photoabsorption, excitation, and solar and stellar atmospheres. Among the most commonly employed approaches are the Kohn variational principle, close-coupling approximation, method of polarized orbitals, R-matrix formulation, and hybrid theory. In every formulation, an attempt is made to include exchange, long-range and short-range correlations, and to make the approach variationally correct. The present formulation, namely, hybrid theory, which is discussed in greater detail compared to other approximations, includes exchange, long-range correlations, and short-range correlations at the same time, and is variationally correct. It was applied to calculate the phase shifts for elastic scattering, the resonance parameters of two-electron systems, photoabsorption in two-electron systems, excitation of atomic hydrogen by an electron and positron impact, and to study the opacity of the Sun’s atmosphere. Calculations of polarizabilities, Rydberg states, and bound states of atoms are also discussed.

Short and long range contributions to the inductive effect in π electron systems

1966 ◽  
Vol 291 (1425) ◽  
pp. 224-234 ◽  
Keyword(s):  
Long Range ◽  
Field Effect ◽  
Short Range ◽  
Inductive Effect ◽  
Electron Systems ◽  
Methyl Group ◽  
Range Type ◽  
Coulomb Type ◽  
Exchange Repulsion ◽  
Coulomb Attraction

It is shown that the inductive effect of a substituent can have contributions of both exchange and Coulomb type, but that the exchange terms can be treated empirically as though they arise from a short-range field effect. Calculations of the exchange terms for the halogens and the methyl group are in accord with the empirical values of inductive parameters deduced from spectroscopy. Evidence is given that for a methyl group the inductive perturbation is almost entirely of short range type and is probably dominated by the exchange terms but for a chloro substituent both the short range exchange repulsion and the long range Coulomb attraction are important.

Smooth nucleon–nucleon interactions and meson theory

1968 ◽  
Vol 46 (8) ◽  
pp. 963-969 ◽  
Author(s):  
Pierre Desgrolard ◽  
J. M. Pearson ◽  
Gérard Saunier
Keyword(s):  
Nuclear Matter ◽  
Long Range ◽  
Short Range ◽  
Singlet State ◽  
Nucleon Nucleon ◽  
Second Order ◽  
Meson Theory ◽  
The One ◽  
Range Part ◽  
Short Range Correlations

Tabakin and Davies have shown that it is possible to fit the singlet-state nucleon–nucleon data with a potential that is smooth enough to give very small second-order terms in an ordinary perturbation–theoretic treatment of nuclear matter. However, their potential is unrealistic in that the requirements of meson theory are in no way satisfied in the long-range region. It is shown here that a potential whose long-range part conforms to the OBEP of Bryan and Scott can still be made to fit the phase shifts without increasing significantly the second-order terms. Thus, with meson theory being incapable of making an unequivocal statement about the short-range region, it will only be by resorting to the experimental evidence for short-range correlations in nuclei that one will be able to resolve the question as to whether or not an interaction as smooth as the one considered here can be regarded as "real" rather than merely "effective". In any event, the existence of such correlations cannot be inferred from the singlet nucleon–nucleon data.

Separation of long-range and short-range interactions in Rydberg states of diatomic molecules

2008 ◽  
Vol 128 (19) ◽  
pp. 194301 ◽  
Author(s):  
Jeffrey J. Kay ◽  
Stephen L. Coy ◽  
Vladimir S. Petrović ◽  
Bryan M. Wong ◽  
Robert W. Field
Keyword(s):  
Long Range ◽  
Short Range ◽  
Diatomic Molecules ◽  
Rydberg States

scholarly journals LONG-RANGE FRACTAL CORRELATIONS IN LITERARY CORPORA

Fractals ◽  
2002 ◽  
Vol 10 (04) ◽  
pp. 451-461 ◽  
Author(s):  
MARCELO A. MONTEMURRO ◽  
PEDRO A. PURY
Keyword(s):  
Long Range ◽  
Short Range ◽  
Fractal Structure ◽  
Written Language ◽  
Long Range Correlations ◽  
Large Samples ◽  
Sentence Level ◽  
Set Up ◽  
Short Range Correlations ◽  
Linguistic Basis

In this paper, we analyze the fractal structure of long human language records by mapping large samples of texts onto time series. The particular mapping set up in this work is inspired on linguistic basis in the sense that is retains the word as the fundamental unit of communication. The results confirm that beyond the short-range correlations resulting from syntactic rules acting at sentence level, long-range structures emerge in large written language samples that give rise to long-range correlations in the use of words.

Long-Range Ordered Phases without Short-Range Correlations

1988 ◽  
Vol 61 (13) ◽  
pp. 1493-1496 ◽  
Author(s):  
V. K. Kabra ◽  
Dhananjai Pandey
Keyword(s):  
Long Range ◽  
Short Range ◽  
Ordered Phases ◽  
Short Range Correlations

scholarly journals Basic features of correlated ion stopping in plasmas

1996 ◽  
Vol 14 (4) ◽  
pp. 749-763 ◽  
Author(s):  
Günter Zwicknagel ◽  
Claude Deutsch
Keyword(s):  
Long Range ◽  
Correlation Length ◽  
Short Range ◽  
Single Individual ◽  
Screening Length ◽  
Long Range Correlations ◽  
Ion Clusters ◽  
Large Ratio ◽  
Basic Features ◽  
Short Range Correlations

We reconsider correlated ion stopping in plasmas with the aim to emphasize the basic features and their underlying physics. For a better understanding of the effects connected with correlated ion stopping, it is useful to distinguish two types of correlated ion stopping, characterized by a small or large ratio of the correlation length of the ions to the screening length in the plasma. These two types of correlated ion stopping are of rather different character. We describe and explain these differences and give some generic examples of ion structures and ion clusters to demonstrate the basic features of both types of correlated stopping. This shows that only the short-range correlations always yield an enhanced stopping, whereas the long-range correlations, in general, reduce the stopping compared to single, individual ions. We mainly consider classical plasmas; the basic features, however, remain unchanged for a jellium target as well as for a plasma at any degeneracy.

DEUTERON-PROTON ELASTIC SCATTERING AT 1.25 GeV/u

2011 ◽  
Vol 26 (03n04) ◽  
pp. 668-670
Author(s):  
◽  
PAVEL K. KURILKIN
Keyword(s):  
Elastic Scattering ◽  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Short Range ◽  
Center Of Mass ◽  
Angular Range ◽  
Mass System ◽  
Proton Elastic Scattering ◽  
Short Range Correlations

Preliminary results on the differential cross section in dp elastic scattering has been obtained at 1.25 GeV/u with HADES within a large angular range in the center of mass system. The obtained data correspond to large transverse momenta, where a sensitivity to the 2 N and 3 N short range correlations is expected.

Pseudorapidity distribution and cluster formation in 50 and 400 GeV/c hadron–nucleus interactions

1984 ◽  
Vol 62 (3) ◽  
pp. 230-238 ◽  
Author(s):  
M. Irfan ◽  
H. Khushnood ◽  
A. Shakeel ◽  
A. R. Khan ◽  
M. Shafi
Keyword(s):  
Long Range ◽  
Short Range ◽  
Dominant Role ◽  
Cluster Formation ◽  
Pseudorapidity Distribution ◽  
Appreciable Change ◽  
Long Range Correlations ◽  
Rapidity Gap ◽  
Rapidity Distributions ◽  
Short Range Correlations

From the study of the pseudorapidity, η, distributions of charged shower particles produced in 50 GeV/c π− – nucleus and 400 GeV/c proton (p)–nucleus collisions, and their dependence on various parameters, the maxima of η distributions are noticed to shift towards smaller values of η with increasing Ng. Bimodality in the η distributions for all Ng groups has been observed to be completely absent in 50 GeV/c π− – nucleus interactions. Furthermore, the value of [Formula: see text] is found to decrease monotonically with increasing Ng, Ns, and Nh. The dispersions of the rapidity distributions D(η) do not, however, demonstrate any tendency of appreciable change with increasing Ng, except in the region of small Ng values. Finally, study of rapidity-gap length distributions reveals that the two-particle short-range correlations play a dominant role while the contribution of long-range correlations seems to be quite small.

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