Study of giant dipole resonances for neodymium isotopes with an exciton model

The partial photonuclear [Formula: see text], pn) and [Formula: see text] and the total photonuclear cross-sections (the giant dipole resonance (GDR)) have been investigated theoretically for neodymium isotopes, namely [Formula: see text]Nd, using framework of the EMPIRE 3.2.2 code. The energy, width and cross-section parameters of the GDR used in our calculations have been investigated in this paper depending on the deformation parameters of nuclei. The calculated results have been compared with the experimental data and with those calculated using Lorentzian fitting parameters. Our calculations show a good agreement for all isotopes under study and give better results than the results calculated with Lorentzian parameters. Furthermore, the neutron number dependence of the total and partial photonuclear cross-sections has also been discussed. The results appear that the EMPIRE code used is a perfect tool for reproducing the splitting in the GDR for deformed [Formula: see text]Nd isotope in two distinct dipole modes which are perfectly consistent with the experimental results. It has also been shown that the present parameters are suitable parameters for reproducing the GDR for spherical, or nearly spherical, and the deformed ([Formula: see text]Nd) neodymium isotopes. The parameters have been indicating the small deformation in [Formula: see text]Nd, which cannot be shown by the Lorentzian fitting parameters.

Download Full-text

SHAPE ISOMERISM OF SODIUM CLUSTERS WITH QUADRUPOLE, OCTUPOLE, AND HEXADECAPOLE DEFORMATIONS IN THE STRUCTURE-AVERAGED JELLIUM MODEL

Surface Review and Letters ◽

10.1142/s0218625x96000450 ◽

1996 ◽

Vol 03 (01) ◽

pp. 229-233 ◽

Cited By ~ 1

Author(s):

TH. HIRSCHMANN ◽

M. BRACK ◽

B. MONTAG ◽

P.-G. REINHARD ◽

J. MEYER

Keyword(s):

Cross Sections ◽

Local Density ◽

Deformation Energy ◽

Jellium Model ◽

Dipole Resonance ◽

Sodium Clusters ◽

Left Right Asymmetry ◽

Singly Charged ◽

Energy Surfaces ◽

Good Agreement

Multidimensional deformation energy surfaces of singly charged sodium clusters with 8≤ Z ≤50 valence electrons have been calculated including quadrupole, octupole, and hexadecapole shapes for the ionic background. We solve the Kohn-Sham equations in the local-density approximation with preserved axial symmetry on a two-dimensional lattice. In addition to the diffusivity of the jellium surface, the structure-averaged jellium model (SAJM) which yields the empirical bulk properties and surface tension of sodium is successfully applied to deformed systems. Discussing the systematics of shape transitions, we find good agreement with recent experimental dipole resonance splittings found in the photoabsorption cross sections and confirm the oblate shape of the first neighboring clusters above the closed 2p shell ( Z =40) provided that left-right asymmetry is enabled.

Download Full-text

Analysis of Reinforced Concrete Culvert considering Concrete Creep and Shrinkage

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198196154100115 ◽

1996 ◽

Vol 1541 (1) ◽

pp. 120-126

Author(s):

Charles J. Oswald

Keyword(s):

Finite Element ◽

Reinforced Concrete ◽

Cross Sections ◽

Soil Structure ◽

Silty Clay ◽

Soil Pressure ◽

Concrete Creep ◽

Long Span ◽

Creep And Shrinkage ◽

Good Agreement

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.

Download Full-text

Disorientation of Cs(62P1/2) atoms, induced in collisions with noble gases

Canadian Journal of Physics ◽

10.1139/p76-085 ◽

1976 ◽

Vol 54 (7) ◽

pp. 748-752 ◽

Cited By ~ 4

Author(s):

B. Niewitecka ◽

L. Krause

Keyword(s):

Cross Sections ◽

Noble Gas ◽

Zero Magnetic Field ◽

Zero Field ◽

Buffer Gas ◽

Resonance Fluorescence ◽

Circularly Polarized ◽

Low Field ◽

Good Agreement ◽

Gas Pressures

The disorientation of 62P1/2 cesium atoms, induced in collisions with noble gas atoms in their ground states, was systematically investigated by monitoring the depolarization of cesium resonance fluorescence in relation to noble gas pressures. The Cs atoms, contained together with a buffer gas in a fluorescence cell and located in zero magnetic field, were excited and oriented by irradiation with circularly polarized 8943 Å resonance radiation, and the resonance fluorescence, emitted in an approximately backward direction, was analyzed with respect to circular polarization. The experiments yielded the following disorientation cross sections which have been corrected for the effects of nuclear spin: Cs–He: 4.9 ± 0.7 Å2; Cs–Ne: 2.1 ± 0.3 Å2; Cs–Ar: 5.6 ± 0.8 Å2; Cs–Kr: 5.8 ± 0.9 Å2; Cs–Xe: 6.3 ± 0.9 Å2. The results are in good agreement with most of the available zero-field and low-field data.

Download Full-text

Atmospheric Lifetimes, Infrared Absorption Spectra, Radiative Forcings and Global Warming Potentials of NF<sub>3</sub> and CFC-115

10.5194/acp-2016-231 ◽

2016 ◽

Author(s):

Anna Totterdill ◽

Tamás Kovács ◽

Wuhu Feng ◽

Sandip Dhomse ◽

Christopher J. Smith ◽

...

Keyword(s):

Global Warming ◽

Cross Sections ◽

Infrared Absorption ◽

Radiative Forcing ◽

Climate Model ◽

Radiative Forcings ◽

Atmospheric Window ◽

Infrared Absorption Spectra ◽

Global Warming Potentials ◽

Good Agreement

Abstract. Fluorinated compounds such as NF3 and C2F5Cl (CFC-115) are characterised by very large global warming potentials (GWPs) which result from extremely long atmospheric lifetimes and strong infrared absorptions in the atmospheric window. In this study we have experimentally determined the infrared absorption cross-sections of NF3 and CFC-115, calculated the radiative forcing and efficiency using two radiative transfer models and identified the effect of clouds and stratospheric adjustment. The infrared cross sections are in good agreement with previous measurements, whereas the resulting radiative forcings and efficiencies are, on average, around 10 % larger. A whole atmosphere chemistry-climate model was used to determine the atmospheric lifetimes of NF3 and CFC-115 to be (616 ± 34) years and (492 ± 22) years, respectively. The GWPs for NF3 are estimated to be 14 600, 19 400 and 21 400 over 20, 100 and 500 years, respectively. Similarly, the GWPs for CFC-115 are 6120, 8060 and 8630 over 20, 100 and 500 years, respectively.

Download Full-text

Electron-impact double ionization of the carbon atom

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834303 ◽

2018 ◽

Vol 620 ◽

pp. A188 ◽

Cited By ~ 6

Author(s):

Valdas Jonauskas

Keyword(s):

Carbon Atom ◽

Electron Impact ◽

Cross Sections ◽

Double Ionization ◽

Impact Excitation ◽

Rate Coefficients ◽

Electron Impact Excitation ◽

Ionization Cross ◽

Ionization Cross Sections ◽

Good Agreement

Electron-impact single- and double-ionization cross sections and Maxwellian rate coefficients are presented for the carbon atom. Scaling factors are introduced for the electron-impact excitation and ionization cross sections obtained in the distorted wave (DW) approximation. It is shown that the scaled DW cross sections provide good agreement with measurements for the single ionization of the C atom and C1+ ion. The direct double-ionization (DDI) process is studied using a multi-step approach. Ionization–ionization, excitation–ionization–ionization, and ionization–excitation–ionization branches are analyzed. It is demonstrated that the three-step processes contribute ≼40% of the total DDI cross sections for the case where one of the electrons takes all of the excess energy after the first ionization process.

Download Full-text

L X-ray fluorescence cross sections in the atomic region 59 ≤ Z ≤ 82 excited by 16.58 keV photons

Canadian Journal of Physics ◽

10.1139/p96-035 ◽

1996 ◽

Vol 74 (5-6) ◽

pp. 230-235 ◽

Cited By ~ 2

Author(s):

D. V. Rao ◽

R. Cesareo ◽

G. E. Gigante

Keyword(s):

Excitation Energy ◽

Least Squares ◽

Cross Sections ◽

Experimental Results ◽

X Ray ◽

Experimental Cross ◽

Average Fluorescence ◽

Good Agreement

LL, Lα, Lβ, and Lγ X-ray fluorescence cross sections for Pr, Sm, Gd, Dy, Ho, Er, Yb, Pt Au, and Pb were measured at the excitation energy 16.58 keV. An X-ray tube and a secondary excitor system was used instead of radioisotopes for the measurements. Experimental cross sections are compared with the theoretical estimates based on relativistic Dirac–Hartree–Slater theory. Average L-shell fluorescence yields [Formula: see text] are deduced using the present experimental cross sections and the theoretical subshell photoionization cross sections. The derived average fluorescence yields are fitted by least squares to polynomials in Z of the form ΣnanZn and compared with theoretical and earlier fitted values. Good agreement is observed ' between the experimental results and the theoretical estimates based on relativistic Dirac–Hartree–Slater theory.

Download Full-text

A comparison between the cross-sections of the reactions35Cl(p, γ)36Ar and37Cl(p, γ)38Ar in the region of the giant dipole resonance

Lettere al Nuovo Cimento ◽

10.1007/bf02755498 ◽

1970 ◽

Vol 3 (14) ◽

pp. 461-465 ◽

Cited By ~ 6

Author(s):

K. G. Kernbach

Keyword(s):

Cross Sections ◽

Giant Dipole Resonance ◽

Dipole Resonance ◽

The Cross

Download Full-text

CROSS-SECTIONS FOR PHOTONUCLEAR REACTIONS 93Nb(γ,n)92mNb AND 93Nb(γ,n)92tNb IN THE END-POINT BREMSSTRAHLUNG ENERGIES 36...91 MeV

10.46813/2020-127-148 ◽

2020 ◽

pp. 148-153

Author(s):

A.N. Vodin ◽

O.S. Deiev ◽

I.S. Timchenko ◽

S.N. Olejnik ◽

A.S. Kachan ◽

...

Keyword(s):

Energy Range ◽

Cross Sections ◽

Maximum Energy ◽

Reaction Cross ◽

Bremsstrahlung Spectrum ◽

Photonuclear Reactions ◽

End Point ◽

Γ Ray ◽

First Time ◽

Good Agreement

The flux-weighted averaged over the energy range of bremsstrahlung spectrum from reaction threshold up to the maximum energy of γ-ray cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb photonuclear reactions were determined by the gamma-activation method within the end-point bremsstrahlung energies Еmax = 36…91 MeV. Activation of 93Nb targets has been done by a bremsstrahlung flux using an electron beam at the linear accelerator LUE-40 at RDC "Accelerator" NSC KIPT. The γ-ray spectra of irradiated targets were registered using the HPGe detector with an energy resolution of 1.8 keV for the 1332 keV line 60Co. To control the bremsstrahlung flux we used natMo witness-targets and a reaction cross-section of 100Mo(γ,n)99Mo. Obtained experimental cross-sections <σ(E)> of the studied reactions are in good agreement with the theoretical values calculated within TALYS 1.9 code and the results of other authors. The averaged cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb reactions in the energy range 35...45 MeV and > 70 MeV were obtained for the first time.

Download Full-text

Energy Dependence of Total Cross Sections for Reactions with 4, 6he, 6, 7, 9li Nuclei

KnE Energy ◽

10.18502/ken.v3i1.1717 ◽

2018 ◽

Vol 3 (1) ◽

pp. 21

Author(s):

Yu Penionzhkevich ◽

Yu Sobolev ◽

V Samarin ◽

M Naumenko

Keyword(s):

Experimental Data ◽

Energy Range ◽

Numerical Solution ◽

Energy Dependence ◽

Cross Sections ◽

Beam Energy ◽

Microscopic Analysis ◽

Time Dependent ◽

Total Cross Sections ◽

Good Agreement

The paper presents the results of measurement of the total cross sections for reactions 4,6He + Si and 6,7,9Li + Si in the beam energy range 5−50 A⋅MeV. The enhancements of the total cross sections for reaction 6He + Si compared with reaction 4He + Si, and 9Li + Si compared with reactions 6,7Li + Si have been observed. The performed microscopic analysis of total cross sections for reactions 6He + Si and 9Li + Si based on numerical solution of the time-dependent Schrödinger equation for external neutrons of projectile nuclei 6He and 9Li yielded good agreement with experimental data.

Download Full-text