Electric dipole transitions from the 11.08 and 9.15 MeV levels in 17O

1983 ◽  
Vol 61 (11) ◽  
pp. 1486-1489 ◽  
Author(s):  
C. Rangacharyulu ◽  
M. B. Chatterjee ◽  
C. Pruneau ◽  
C. St-Pierre
Keyword(s):  
Excellent Agreement ◽  
Electric Dipole ◽  
Transition Strength ◽  
Core Polarization ◽  
The Core ◽  
Polarization Charge ◽  
Analogous Formula ◽  
The Asymmetry ◽  
Polarization Calculation

In the 13C(α, γ)17O reaction, measurements of E1 transition strengths from the 11.078 and 9.148 MeV (Jπ = 1/2−) levels to the 0.871 MeV level give (10.4 ± 1.6) × 10−3and (2.4 ± 0.5) × 10−3 e2 fm2, respectively. The ratio of these transition strengths results in a polarization charge epol ≈ −0.6. The E1 transition strength from the 11.078 MeV level is in excellent agreement with the core-polarization calculation of Towner and Hardy. The asymmetry for the corresponding isovector E1 transitions in 17O and 17F is found to be [Formula: see text], comparable in magnitude with the asymmetry for the analogous [Formula: see text] decays of 17N and 17Ne.

scholarly journals Microscopic calculations of the electric Quadrupole transition strengths of Be isotopes (9, 10, 12, 14)

2019 ◽  
Vol 12 (24) ◽  
pp. 87-99
Author(s):  
Sara. H. Ibrahim
Keyword(s):  
Harmonic Oscillator ◽  
Shell Model ◽  
Electric Quadrupole ◽  
Transition Strength ◽  
Matrix Elements ◽  
Core Polarization ◽  
Model Calculations ◽  
Polarization Effects ◽  
The Core ◽  
Effective Charges

Electric Quadrupole transitions are calculated for beryllium isotopes (9, 10, 12 and 14). Calculations with configuration mixing shell model usually under estimate the measured E2 transition strength. Although the consideration of a large basis no core shell model with 2ℏtruncations for 9,10,12 and14 where all major shells s, p, sd are used, fail to describe the measured reduced transition strength without normalizing the matrix elements with effective charges to compensate for the discarded space. Instead of using constant effective charges, excitations out of major shell space are taken into account through a microscopic theory which allows particle–hole excitations from the core and model space orbits to all higher orbits with 2ℏw excitations which are called core-polarization effects. The two body Michigan sum of three ranges Yukawa potential (M3Y) is used for the core-polarization matrix element. The simple harmonic oscillator potential is used to generate the single particle matrix elements of all isotopes considered in this work. The b value of each isotope is adjusted to reproduce the experimental matter radius, These size parameters of the harmonic oscillator almost reproduce all the root mean square (rms) matter radii for 9,10,12,14Be isotopes within the experimental errors. Almost same effective charges are obtained for the neutron- rich Be isotopes which are smaller than the standard values. The major contribution to the transition strength comes from the core polarization effects. The present calculations of the neutron-rich 12,14Beisotopes show a deviation from the general trends in accordance with experimental and other theoretical studies. The configurations arises from the shell model calculations with core-polarization effects reproduce the experimental B(E2) values.

Relative clauses in Agul from a corpus-based perspective

2020 ◽  
Vol 73 (1) ◽  
pp. 113-158
Author(s):  
Timur Maisak
Keyword(s):  
High Frequency ◽  
Relative Clauses ◽  
High Ratio ◽  
The Other ◽  
The Core ◽  
Text Corpora ◽  
The Asymmetry ◽  
Intransitive Verbs ◽  
Syntactic Restrictions ◽  
Locative Case

AbstractThis paper gives an account of participial clauses in Agul (Lezgic, Nakh-Daghestanian), based on a sample of 858 headed noun-modifying clauses taken from two text corpora, one spoken and one written. Noun-modifying clauses in Agul do not show syntactic restrictions on what can be relativized, and hence they instantiate the type known as GNMCCs, or general noun-modifying clause constructions. As the text counts show, intransitive verbs are more frequent than transitives and experiencer verbs in participial clauses, and among intransitive verbs, locative statives with the roots ‘be’ and ‘stay, remain’ account for half of all the uses. The asymmetry between the different relativization targets is also significant. Among the core arguments, the intransitive subject (S) is the most frequent target, patient (P) occupies second place, and agent (A) is comparatively rare. The preference of S and, in general, of S and P over A also holds true for most other Nakh-Daghestanian languages for which comparable counts are available. At the same time, Agul stands apart from the other languages by its high ratio of non-core relativization which accounts for 42% of all participial clauses. Addressee, arguments and adjuncts encoded with a locative case, as well as more general place and time relativizations show especially high frequency, outnumbering such arguments as experiencers, recipients, and predicative and adnominal possessors. Possible reasons for the high ratio of non-argument relativization are discussed in the paper.

scholarly journals O2 State in 18 O by using Core – Polarization effects

2008 ◽  
pp. 66-72
Keyword(s):  
Perturbation Theory ◽  
Experimental Studies ◽  
Form Factors ◽  
Wave Model ◽  
Collective Model ◽  
Core Polarization ◽  
Polarization Effects ◽  
The Core ◽  
The Subject ◽  
Space Wave

Coulomb form factors for E0 transition in 18O are discussed taking into account core-polarization effects. These effects are taken into account through the collective model of Tassie and also through a microscopic perturbation theory including excitations up to 2p1f shell. Space wave model functions defined for the orbits 1 and 2125O nucleus has been the subject of extensive theoretical and experimental studies, which received much attention in last decade [Alex Brown et.al.2005]. The 18O system contains two neutrons in addition to the16O core distributed in the sd – shell. d1 are obtained from the diagonalization of the interaction Hamilonian of Wildenthal. The calculations include the 0 2state with excitation energies3.6337MeV. The core – polarization effects which incorporate the ollective model of Tassei describe the data very well for this state.

Influence of the core polarization on the dielectric properties of polyvalent metals

1998 ◽  
Vol 6 (3) ◽  
pp. 323-328 ◽  
Author(s):  
M. Knupfer ◽  
K. Widder ◽  
M. Sing ◽  
O. Knauff ◽  
J. Fink
Keyword(s):  
Dielectric Properties ◽  
Core Polarization ◽  
The Core

Calculation of the Knight Shift in Palladium

1979 ◽  
Vol 34 (4) ◽  
pp. 523-524 ◽  
Author(s):  
R. Krieger ◽  
J. Voitländer
Keyword(s):  
Fermi Surface ◽  
Knight Shift ◽  
Enhancement Factor ◽  
Negative Contribution ◽  
Core Polarization ◽  
Conduction Electrons ◽  
The Core ◽  
Core Electrons ◽  
Palladium Metal ◽  
Good Agreement

The direct and core-polarization contributions to the Knight shift in palladium metal have been calculated taking an enhancement factor of 10 for d- and 1.28 for s-electrons. We found a large negative contribution of - 3.88% for the core electrons and a comparatively small direct contribution of 0.18% for s-electrons on the Fermi surface. Together with an estimated contribution of 0.36% for conduction electrons in s-orbitals, but not on the Fermi surface, the calculated total amount of - 3.34% is in good agreement with the experimental value of - 4% obtained by the Jaccarino plot for palladium at 0 K

Effects of the isoscalar and isovector interaction on the ground-state magnetic moments of odd-mass 137–145Ce nuclei

2019 ◽  
Vol 97 (11) ◽  
pp. 1187-1190
Author(s):  
H. Yakut ◽  
E. Tabar ◽  
G. Hoşgör
Keyword(s):  
Ground State ◽  
Magnetic Moments ◽  
The Other ◽  
Spin Interaction ◽  
Nuclear Model ◽  
Isotopic Chain ◽  
Core Polarization ◽  
Polarization Effects ◽  
The Core

A systematic study of the magnetic properties of deformed odd-neutron 137–145Ce isotopes using the microscopic quasiparticle phonon nuclear model (QPNM) has been presented. The QPNM includes residual spin–spin interaction in both isoscalar and isovector channels. The analysis shows that in the isoscalar channel contributions to the magnetic moment coming from the neutron and proton systems practically cancel out each other. On the other hand, in the isovector channel, the coherent contribution coming from the quasiparticle–phonon interactions leads to a spin polarization (core polarization), which is important for determination of the quenched spin gyromagnetic factors (gs). The quenched spin gyromagnetic factors so called [Formula: see text] have been found to range from [Formula: see text] to [Formula: see text] in the odd-mass 137–145Ce isotopic chain, which is similar to its phenomenological value ([Formula: see text] between [Formula: see text] and [Formula: see text]). By taking into consideration the core polarization effects, the available experimental data are satisfactorily reproduced with an accuracy of 0.01μN–0.1μN.

Hyperfine structure of Eu I

1965 ◽  
Vol 289 (1416) ◽  
pp. 81-96 ◽  
Keyword(s):  
Theoretical Analysis ◽  
Hyperfine Structure ◽  
Relativistic Effects ◽  
Interaction Constant ◽  
Tensor Operator ◽  
Quadrupole Moments ◽  
Core Polarization ◽  
The Core ◽  
Least Squares Fit ◽  
Good Agreement

A theoretical analysis is made of the hyperfine structure of the twelve levels of Eu I 4 f 7 ( 8 S ) 6 s 6 p using intermediate-coupled eigenfunctions obtained from a least-squares fit of the energies of the levels. Relativistic effects for the 6 p electron are calculated throughout by tensor-operator techniques. Good agreement is obtained with the observed A values, treating as parameters the polarization of the core (by the f electrons) and the hyperfine interaction constant of the 6 s electron. The magnitude of the core polarization is related to data on Eu I 4 f 7 ( 8 S ) 6s 2 , Euii 4 f 7 ( 8 s ) 6 s , and Eu III 4 f 7 ( 8 S ). The hyperfine-structure anomalies also fall into a consistent pattern. The observed B values are related to quadrupole moments of 151 Eu and 153 Eu.

High Temperature NMR Study of 51V and 195Pt in the V3Pt Compound

1984 ◽  
Vol 39 (2) ◽  
pp. 145-147
Author(s):  
R. Rünger ◽  
D. Ploumbidis
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Knight Shift ◽  
Core Polarization ◽  
Temperature Coefficients ◽  
Polarization Contribution ◽  
The Core ◽  
Nmr Study

Measurements of both the 51V and 195Pt Knight shift in the V3Pt compound are reported for temperatures ranging from 300 K to about 1300 K. The temperature coefficients of the Knight shift and the NMR linewidth have been determined. An interpretation of the observations is given in the frame of a model which is based on the temperature dependence of the core polarization contribution to the total Knight shift.

scholarly journals The EDC3 chronology for the EPICA Dome C ice core

2007 ◽  
Vol 3 (3) ◽  
pp. 485-497 ◽  
Author(s):  
F. Parrenin ◽  
J.-M. Barnola ◽  
J. Beer ◽  
T. Blunier ◽  
E. Castellano ◽  
...  
Keyword(s):  
Pattern Matching ◽  
Time Scales ◽  
Excellent Agreement ◽  
Time Scale ◽  
Flow Model ◽  
Ice Core ◽  
Snow Accumulation ◽  
The Core ◽  
Time Periods ◽  
Paleoclimatic Records

Abstract. The EPICA (European Project for Ice Coring in Antarctica) Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new EDC3 chronology, which is based on the use of 1) a snow accumulation and mechanical flow model, and 2) a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation variations. We show that this new time scale is in excellent agreement with the Dome Fuji and Vostok ice core time scales back to 100 kyr within 1 kyr. Discrepancies larger than 3 kyr arise during MIS 5.4, 5.5 and 6, which points to anomalies in either snow accumulation or mechanical flow during these time periods. We estimate that EDC3 gives accurate event durations within 20% (2σ) back to MIS11 and accurate absolute ages with a maximum uncertainty of 6 kyr back to 800 kyr.

scholarly journals ELASTIC AND INELASTIC ALPHA TRANSFER IN THE 16O+12C SCATTERING

2021 ◽  
Vol 31 (4) ◽  
Author(s):  
Phuc Hoang Nguyen ◽  
Phuc Tri Toan Nguyen ◽  
Khoa Tien Dao
Keyword(s):  
Cross Section ◽  
Heavy Ion ◽  
Scattering Cross Section ◽  
Transition Strength ◽  
Valence Nucleon ◽  
The Core ◽  
Scattering Cross ◽  
Oscillatory Pattern ◽  
Reaction Channels ◽  
Coupled Reaction

The elastic scattering cross section measured at energies $E\lesssim 10$ MeV/nucleon for some light heavy-ion systems having two identical cores like \oc exhibits an enhanced oscillatory pattern at the backward angles. Such a pattern is known to be due to the transfer of the valence nucleon or cluster between the two identical cores. In particular, the elastic $\alpha$ transfer has been shown to originate directly from the core-exchange symmetry in the elastic \oc scattering. Given the strong transition strength of the $2^+_1$ state of $^{12}$C and its large overlap with the $^{16}$O ground state, it is natural to expect a similar $\alpha$ transfer process (or inelastic $\alpha$ transfer) to take place in the inelastic \oc scattering. The present work provides a realistic coupled channel description of the $\alpha$ transfer in the inelastic \oc scattering at low energies. Based on the results of the 4 coupled reaction-channels calculation, we show a significant contribution of the $\alpha$ transfer to the inelastic \oc scattering cross section at the backward angles. These results suggest that the explicit coupling to the $\alpha$ transfer channels is crucial in the studies of the elastic and inelastic scattering of a nucleus-nucleus system with the core-exchange symmetry.\Keywords{optical potential, coupled reaction channels, inelastic $\alpha$ transfer

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