Autoionization resonances in the argon iso-electronic sequence

2012 ◽  
Vol 90 (6) ◽  
pp. 547-555 ◽  
Author(s):  
Juby George ◽  
G.B. Pradhan ◽  
Milind Rundhe ◽  
Jobin Jose ◽  
G. Aravind ◽  
...  
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Ionic Species ◽  
Theoretical Studies ◽  
Isoelectronic Sequence ◽  
Quantum Defect Theory ◽  
Theoretical Results ◽  
Good Agreement

We report results of theoretical studies of 3s → np and 2s → np autoionization resonances, respectively, in the 3p and the 2p photoionization cross sections of a few members (Ar, K+, Ca2+, Fe8+, Zn12+, and Kr18+) of the argon isoelectronic sequence, within the framework of the relativistic random phase approximation and using the relativistic multichannel quantum defect theory. The present approach would enable analysis of complex atomic spectra especially of atomic and (or) ionic species that are found in stellar gases in a computationally economical way. The shape profiles of the autoionization resonances have been analyzed in the present work using appropriate Fano parameters. The quantum defects determined for some of the lower or intermediate excited states are found to be in good agreement with the experimental and (or) theoretical results.

Many-Electron Correlations in the Photoionization of a Nitrogen Atom

1974 ◽  
Vol 52 (4) ◽  
pp. 349-354 ◽  
Author(s):  
N. A. Cherepkov ◽  
L. V. Chernysheva ◽  
V. Radojević ◽  
I. Pavlin
Keyword(s):  
Nitrogen Atom ◽  
Cross Section ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Electron Correlations ◽  
Sum Rule ◽  
Hartree Fock ◽  
The Cross ◽  
Good Agreement

Photoionization cross sections for the outer shell of the nitrogen atom ground state are calculated in the single-particle Hartree–Fock approximation and, in order to take into account many-electron correlations, also in the Random Phase Approximation with Exchange (RPAE). To be able to apply the RPAE, its modification for the half-filled shell atom, such as nitrogen atom, is presented. Calculation of length and velocity forms of the cross section in both approximations are compared with the available experimental data, and a good agreement is obtained. It has been found that in the RPAE the influence of many-electron correlations in a nitrogen atom is not great, but it is very important since, in contrast to the Hartree–Fock approximation, it results in the validity of the sum rule and the coincidence of the length and velocity forms of the cross sections, in agreement with the requirement of the general theory. The angular distribution of photoelectrons is also calculated in the RPAE, which has not been measured so far.

Analysis of Collective Resonances in Clusters: Metals and Carbon

1992 ◽  
Vol 272 ◽  
Author(s):  
Vitaly V. Kresin
Keyword(s):  
Random Phase Approximation ◽  
Sum Rules ◽  
Random Phase ◽  
Closed Shell ◽  
Dynamical Response ◽  
Many Body ◽  
Resonance Frequencies ◽  
Unified View ◽  
Small Clusters ◽  
Good Agreement

ABSTRACTDipole photoabsorption spectra of small clusters are analyzed. Two types of systems are considered: metal clusters and the carbon fullerenes. Both have been found to exhibit strong collective photoabsorption modes associated with the motion of delocalized electrons. We describe analytical results for the resonance frequencies in both spherical (closed-shell metallic, C60 ) and spheroidal (openshell metallic, C70) particles. The calculation is based on the techniques of many-body physics (random-phase approximation, sum rules), affords a unified view of the dynamical response of microscopic clusters, and leads to good agreement with experimental data.

scholarly journals Nuclear response to supernova neutrino spectra

2019 ◽  
Vol 18 ◽  
pp. 187
Author(s):  
V. Tsakstara ◽  
T. S. Kosmas ◽  
J. Sinatkas
Keyword(s):  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Rare Event ◽  
Double Beta Decay ◽  
Low Energy ◽  
Quasi Particle ◽  
Supernova Neutrino ◽  
Nuclear Targets ◽  
Nuclear Response

In current probes searching for rare event processes, appropriate nuclear targets are employed (in the COBRA double-beta decay detector the CdZnTe semiconductor is used). In this work the response of such detectors to various low-energy neutrino spectra is explored starting from state-by-state calculations of the neutrino-nucleus reactions cross sections obtained by using the quasi particle random phase approximation (QRPA) based on realistic two-body residual interactions. As a concrete example, we examine the response of 64Zn isotope to low energy supernova neutrinos.

The electric dipole response of even-even 154-164Dy isotopes

2022 ◽  
Author(s):  
Huseynqulu Quliyev ◽  
Nilufer Demirci Saygı ◽  
Ekber Guliyev ◽  
Ali Akbar Kuliev
Keyword(s):  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Electric Response ◽  
Quasiparticle Random Phase Approximation ◽  
Effective Interactions ◽  
Dipole Resonance ◽  
Pygmy Dipole Resonance ◽  
Strength Functions ◽  
Dipole Response

Abstract The excitation of pygmy dipole resonance (PDR) and giant dipole resonance (GDR) in even-even 154-164Dy isotopes is examined through quasiparticle random-phase approximation (QRPA) with the effective interactions that restores the broken translational and Galilean invariances. In each isotope, an electric response emerges by showing ample distribution at energies below and above 10 MeV. We, therefore, study the transition cross sections and probabilities, photon strength functions, transition strengths, isospin character, and collectivity of the predicted E1 responses.

Quasiparticle nature of excited states in random-phase approximation

2019 ◽  
Vol 99 (1) ◽  
Author(s):  
E. V. Chimanski ◽  
B. V. Carlson ◽  
R. Capote ◽  
A. J. Koning
Keyword(s):  
Excited States ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation

scholarly journals Analysis of the Intermediate-State Contributions to Neutrinoless Doubleβ−Decays

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Juhani Hyvärinen ◽  
Jouni Suhonen
Keyword(s):  
Excited States ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Form Factors ◽  
Nuclear Model ◽  
Quasiparticle Random Phase Approximation ◽  
Boson Exchange ◽  
Majorana Neutrinos ◽  
Nucleon Form Factors ◽  
Short Range Correlations

A comprehensive analysis of the structure of the nuclear matrix elements (NMEs) of neutrinoless double beta-minus (0νβ-β-) decays to the0+ground and first excited states is performed in terms of the contributing multipole states in the intermediate nuclei of0νβ-β-transitions. We concentrate on the transitions mediated by the light (l-NMEs) Majorana neutrinos. As nuclear model we use the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic two-nucleon interaction based on the Bonn one-boson-exchangeGmatrix. In the computations we include the appropriate short-range correlations, nucleon form factors, and higher-order nucleonic weak currents and restore the isospin symmetry by the isoscalar-isovector decomposition of the particle-particle proton-neutron interaction parametergpp.

In-Plane Vibrations of Thick Circular Rings With T or I Cross Sections

1979 ◽  
Vol 46 (2) ◽  
pp. 470-472
Author(s):  
H. Lecoanet ◽  
J. Piranda
Keyword(s):  
Experimental Data ◽  
Eigenvalue Problem ◽  
Cross Section ◽  
Cross Sections ◽  
Rectangular Cross Section ◽  
Circular Rings ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with the problem of eigenfrequencies and eigenvectors for rings whose cross section may be decomposed in basic rectangular cross sections. The solution is derived from a solution of the in-plane eigenvalue problem for rectangular cross-section thick rings. A good agreement between theoretical results and experimental data is obtained.

Relativistic-random-phase approximation calculations of atomic photoionization: what we have learned

2009 ◽  
Vol 87 (1) ◽  
pp. 5-8 ◽  
Author(s):  
S T Manson
Keyword(s):  
Angular Distribution ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Branching Ratios ◽  
Phase Approximation ◽  
The Past ◽  
Photoionization Process ◽  
Photoelectron Angular Distribution ◽  
Made In

The relativistic-random-phase approximation (RRPA) methodology, developed by Walter Johnson and his collaborators, has been used extensively over the past three decades to calculate various aspects of the atomic photoionization process, cross sections, and branching ratios along with dipole and nondipole contributions to the photoelectron angular distribution. In this paper, some of the progress made in our understanding of the photoionization process as a result of RRPA calculations is reviewed.PACS No.: 32.80.Fb

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