Recent Articles

Energy dependence of the ( $p, n$ ) analog cross sections of the molybdenum isotopes between 16 and 26 MeV

S. M. Grimes, C. H. Poppe, J. D. Anderson, J. C. Davis, W. H. Dunlop, and C. Wong

Phys. Rev. C 11, 158 (1975) - Published 1 January, 1975

Show Abstract

The differential cross sections for the ( $p, n$ ) reaction to the ground-state analogs of the seven stable Mo isotopes have been measured for proton energies between 16 and 26 MeV. Integrated cross sections are found to deviate from the expected linear dependence on neutron excess. In addition, the excitation functions show a resonant-type enhancement at about 20 MeV. The ( $N - Z$ ) dependence and energy dependence are not consistent with several possible explanations for deviations from the simple charge exchange model. However, the ( $N - Z$ ) dependence for the even isotopes can be explained in part by the effects of multistep processes.

NUCLEAR REACTIONS ${}^{92, 94, 95, 96, 97, 98, 100}{Mo} (p, n)$ . Ground-state analog, $E = 16, 18, 20, 22, 24, 26$ MeV; measured $σ (θ)$ ; quasielastic ( $p, n$ ) optical model fits; enriched targets.

Coulomb excitation of levels in ${}^{95}{Mo}$ and ${}^{97}{Mo}$

J. Barrette, M. Barrette, R. Haroutunian, G. Lamoureux, S. Monaro, and S. Markiza

Phys. Rev. C 11, 171 (1975) - Published 1 January, 1975

Show Abstract

The properties of the low-lying levels of ${}^{95}{Mo}$ and ${}^{97}{Mo}$ have been investigated via Coulomb excitation which was effected by bombarding isotopically enriched thick targets with 6.0 to 10.0 MeV $α$ particles and 43.4 MeV ${}^{16}O$ ions. Sixteen transitions in ${}^{95}{Mo}$ and twenty three transitions in ${}^{97}{Mo}$ were observed resulting from direct $E 2$ excitation of eight excited states up to an excitation energy of 1073.7 keV in ${}^{95}{Mo}$ , and of thirteen excited states up to an excitation energy of 1515.5 keV in ${}^{97}{Mo}$ . Angular distribution measurements were carried out for several transitions in both nuclei to aid in the assignment of spins and to yield the $E 2$ and $M 1$ contents in these transitions. The level structure of ${}^{95}{Mo}$ and ${}^{97}{Mo}$ and the measured $E 2$ and $M 1$ transition rates are compared with the predictions available for these nuclei.

NUCLEAR REACTIONS ${}^{95, 97}{Mo} (α, α^{'} γ)$ , $E = 6 - 10$ MeV; ${}^{95, 97}{Mo} ({}^{16}O, {}^{16}O^{'} γ)$ , $E = 43.4$ MeV; measured $σ (E_{γ}, θ_{γ})$ , ${}^{95, 97}{Mo}$ deduced levels, $B (E 2)$ , $B (M 1)$ , $T_{\frac{1}{2}}$ , $J$ , $π$ , $γ$ mixing, $γ$ branching. Enriched targets.

Rotational band structure in $N = 105 and 107$ isotones: I. Evidence for the transition to $| I Rj 〉$ coupling at high spins in ${}^{179}W$

F. M. Bernthal and R. A. Warner

Phys. Rev. C 11, 188 (1975) - Published 1 January, 1975

Show Abstract

The ${}^{177}{Hf} (α, 2 n γ)$ and ${}^{181}{Ta} (p, 3 n γ)$ reactions have been employed in a study of the ${}^{179}W$ rotational band structure. Attention is focused on the unique-parity $\frac{9}{2^{+}} [624]$ band and its highly perturbed rotational structure. The higher-spin members of the even-parity band in ${}^{179}W$ are not well characterized by a single $K$ quantum number and are better represented in the $| I Rj 〉$ weak-coupling scheme. Limits are placed on the hexadecapole deformation consistent with the rotational band structure in ${}^{179}W$ . The relevance of the even-parity band structure in ${}^{179}W$ to backbending in neighboring even- $A$ nuclei is discussed.

NUCLEAR REACTIONS ${}^{177}{Hf} (α, 2 n γ)$ , $E_{α} = 26$ MeV, ${}^{181}{Ta} (p, 3 n γ)$ , $E_{p} = 26$ MeV; measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ coin. Enriched ${}^{177}{Hf}$ target. Deduced ${}^{179}W$ levels, $I$ , $π$ , $K$ . Coriolis calculations, implied nuclear deformation, relevance to "backbending."

Structure of ${}^{20}{Ne}$ : The ${}^{19}F ({}^{3}{He}, d) {}^{20}{Ne}$ reaction

R. R. Betts, H. T. Fortune, and R. Middleton

Phys. Rev. C 11, 19 (1975) - Published 1 January, 1975

Show Abstract

The ${}^{19}F ({}^{3}{He}, d) {}^{20}{Ne}$ reaction has been studied at a bombarding energy of 18 MeV. Levels were identified up to an excitation energy of 13.3 MeV in ${}^{20}{Ne}$ . Several new spin-parity and isospin assignments are made. A comparison of the experimental spectroscopic strengths with those predicted by the Nilsson, SU(3), and shell models shows reasonably good agreement.

NUCLEAR REACTIONS ${}^{19}F ({}^{3}{He}, d)$ , $E = 18$ MeV; measured $σ (E_{d}, θ)$ ; ${}^{20}{Ne}$ deduced levels, $l$ , $J$ , $π$ , $T$ .

Matter radii of the even tin isotopes from elastic $α$ and ${}^{16}O$ scattering

S. L. Tabor, B. A. Watson, and S. S. Hanna

Phys. Rev. C 11, 198 (1975) - Published 1 January, 1975

Show Abstract

The elastic scattering of $α$ and ${}^{16}O$ particles from ${}^{116, 118, 120, 122, 124}{Sn}$ has been measured at $α$ energies between 9 and 17 MeV and at ${}^{16}O$ energies between 46 and 59 MeV. Fits have been made to the data with the optical and the incoming wave boundary condition models. The radius at which the nuclear potential is 2% of the Coulomb potential is minimally sensitive to the ambiguities of the fit. The increases in nuclear matter size as $A$ increases over the tin isotopes, measured by $α$ and by ${}^{16}O$ scattering, agree reasonably well with each other and with the increase measured by proton scattering. However, the increase in the size of the matter distribution is 2 to 3 times larger than that of the charge distribution as observed in muonic atom and electron scattering studies.

NUCLEAR REACTIONS ${}^{116, 118, 120, 122, 124}{Sn} (α, α)$ ,, $E = 9 - 17$ MeV; ${}^{116, 118, 120, 122, 124}{Sn}$ ( ${}^{16}O$ , ${}^{16}O$ ), $E = 46 - 59$ MeV; measured $σ (E, θ)$ . Deduced nuclear size. Enriched targets.

Double $K$ -shell ionization in the internal-conversion decay of ${}^{109}{Ag}^{m}$

H. J. Nagy, G. Schupp, and R. R. Hurst

Phys. Rev. C 11, 205 (1975) - Published 1 January, 1975

Show Abstract

Double ionization of the atomic $K$ shell accompanying the $K$ -shell internal conversion of the 88.0-keV $E 3$ transition of ${}^{109}{Ag}^{m}$ has been studied by recording coincidences between $K$ x rays and $K α$ x rays emitted when the double vacancies are filled. The probability per $K$ -shell internal conversion that a double $K$ -shell vacancy is formed, $T_{KK}$ , was found to be (1.53±0.24) × $10^{- 4}$ , and is about a factor of 5 smaller than a previous measurement. The energy shift, $Δ E$ , of the $K α$ "hypersatellite" x ray was measured to be (373 ± 75) eV.

RADIOACTIVITY ${}^{109}{Ag}^{m}$ ; measured $K$ x-ray— $K α$ x-ray coin., deduced double $K$ -shell ionization probability and $K α$ "hypersatellite" x-ray energy shift.

Microscopic study of the variable-moment-of-inertia model for rare-earth nuclei

Chin W. Ma and Chin Fu Tsang

Phys. Rev. C 11, 213 (1975) - Published 1 January, 1975

Show Abstract

Based on the microscopic cranking model, the moment-of-inertia parameter $J_{0}$ and the force constant $C_{VMI}$ associated with the variable-moment-of-inertia model are calculated microscopically for rare-earth nuclei. Higher-order effects representing quadrupole and hexadecapole centrifugal stretching, proton and neutron Coriolis-antipairing effects, and fourth-order cranking correction are included. The present calculations are able to reproduce the trend and the magnitude of both $J_{0}$ and $C_{VMI}$ fairly well with discrepancies ranging from 10 to 40%.

NUCLEAR STRUCTURE Rare-earth even-even nuclei, calculated moment of inertia and force constant. Variable-moment-of-inertia model, cranking model. Coriolis-antipairing effect, fourth-order cranking, centrifugal stretching.

Quadrupole variation of projected spectra of even Ti isotopes

Harish Chandra and P. Lichtner

Phys. Rev. C 11, 228 (1975) - Published 1 January, 1975

Show Abstract

In the present work we study the dependence of projected good $J$ states on the quadrupole moment. In order to achieve this, the quadrupole-moment-depenent generalized deformed BCS (DBCS) wave functions have been computed after minimizing the constrained Hamiltonian $H_{q} = H - λ N - μ Q$ . The calculation assumes the existence of a ${}^{40}{Ca}$ spherical core. The two body residual interaction between the valence nucleons is determined by using the ${}^{42}{Sc}$ spectrum for the $T = 0$ force and the ${}^{49}{Ca}$ spectrum for the $T = 1$ force. The result of the calculation shows that the projected spectra in general cannot be described by a single DBCS wave function obtained as a result of minimizing the Hamiltonian without a quadrupole constraint.

NUCLEAR STRUCTURE Calculations for ${}^{44}{Ti}$ , ${}^{46}{Ti}$ , ${}^{48}{Ti}$ . Quadrupole dependence of projected good $J$ states.

Matrix solution of the Bethe-Faddeev equations

Dean W. Halderson and Paul Goldhammer

Phys. Rev. C 11, 237 (1975) - Published 1 January, 1975

Show Abstract

The Bethe-Faddeev equations are set up in matrix form and solved for the ${}^{3}H$ nucleus. The two-body $g$ matrix is derived from a revised version of the Brueckner-Bethe-Goldstone formalism. Application to the Reid soft core potential indicates that this interaction yields an eigenvalue very close to the experimental binding energy of ${}^{3}H$ .

NUCLEAR STRUCTURE Three-body correlations, Brueckner-Bethe-Goldstone method, binding energy, ${}^{3}H$ , Reid and Hamada-Johnston potentials.

Nuclear $g$ factors of the ${\frac{21}{2}}^{-}$ and the ${\frac{29}{2}}^{+}$ states in ${}^{211}{At}$

H. Ingwersen, W. Klinger, G. Schatz, and W. Witthuhn

Phys. Rev. C 11, 243 (1975) - Published 1 January, 1975

Show Abstract

The $g$ factors of the ${\frac{21}{2}}^{-}$ (1416.3 keV, $T_{\frac{1}{2}} = 50$ nsec) and the ${\frac{29}{2}}^{+}$ (2641.2 keV, $T_{\frac{1}{2}} = 70$ nsec) states in ${}^{211}{At}$ were measured by the time differential spin rotation method. The experimental results corrected for diamagnetic shielding and Knight shift are $g ({\frac{21}{2}}^{-}) = + 0.917 \pm 0.016$ and $g ({\frac{29}{2}}^{+}) = + 1.073 \pm 0.031$ . The analysis yields an orbital $g$ factor of the proton $g_{t} = 1.12 \pm 0.04$ . The comparison with $g$ factors of other ${(h_{\frac{9}{2}})}^{n}$ proton states in $N = 126$ isotones shows a significant deviation from the predicted blocking of core polarization.

NUCLEAR REACTIONS ${}^{209}{Bi} (α, 2 n)$ , $E = 30, 33$ MeV; measured $γ (θ, H, t)$ . ${}^{211}{At}$ levels deduced $g$ .

Energy dependence of isospin mixing matrix elements

S. M. Grimes

Phys. Rev. C 11, 253 (1975) - Published 1 January, 1975

Show Abstract

Recently published values for the isospin mixing width at energies of 17 to 22 MeV in the nucleus ${}^{69}{Ga}$ are used to infer values for the isospin mixing matrix elements. It is found that these are much smaller in magnitude than those deduced at much lower energies from $β$ decay measurements.

NUCLEAR REACTIONS ${}^{68}{Zn} (p, α)$ , ${}^{68}{Zn} (p, p^{'})$ , ${}^{65}{Cu} (α, p)$ , ${}^{65}{Cu} (α, α^{'})$ forming ${}^{69}{Ga}$ compound nucleus at excitation energies of 17-22 MeV; deduced isospin mixing matrix elements from previously published data.

Magnetic moment of the deuteron and phenomenological models of the nucleon-nucleon interaction

Robert R. Scheerbaum

Phys. Rev. C 11, 255 (1975) - Published 1 January, 1975

Show Abstract

Various aspects of the Yale, Hamada-Johnston, and Reid nucleon-nucleon potentials which pertain to the deuteron magnetic moment are discussed. The total deuteron magnetic moment is calculated for each of these potentials and the results, together with their significance, are briefly discussed.

NUCLEAR MOMENTS ${}^{2}H$ ; calculated magnetic moment in Yale, Hamada-Johnston, and Reid potential models.

Rule for the spins of the lowest state with $T = | T_{Z} |$ of doubly odd nuclei having $j^{n}$ configuration

S. K. Gupta

Phys. Rev. C 11, 259 (1975) - Published 1 January, 1975

Show Abstract

Two empirical rules given earlier have been modified to one rule for the spins of the lowest state with $T = | T_{Z} |$ for the odd-odd nuclei where the valence nucleons are filling the same subshell. The recent measurement on ${}_{9}^{22}F$ follows the new rule. Predictions for the unknown spins have been made. Some remarks have been made about the odd-even nuclei.

NUCLEAR STRUCTURE Rule for spins of doubly odd nuclei with $A = 2 - 92$ , compared with existing data, predicted spins for unknown cases.

RAPID COMMUNICATION

Coulomb-nuclear interference for the ( $d, d^{'}$ ) reaction on isotopes of Nd

F. Todd Baker, W. Hartwig, T. H. Kruse, and E. Ventura

Phys. Rev. C 11, 262(R) (1975) - Published 1 January, 1975

Show Abstract

Excitation functions at 140° laboratory angle have been measured for inelastic deuteron scattering to the first $2^{+}$ states of ${}^{142, 144, 146, 148, 150}{Nd}$ . The anomalous destructive Coulomb-nuclear interference previously observed for other $N = 82$ isotones also occurs for ${}^{142}{Nd}$ . This anomaly is seen to be a sudden change in the nature of the interference rather than a gradual change as one approaches this closed shell.

NUCLEAR REACTIONS ${}^{142, 144, 146, 148, 150}{Nd} (d, d^{'})$ , $E = 5 - 16$ MeV; measured $σ (E)$ at $θ_{lab} = 140 °$ . Deduced deformation parameters $β_{2}$ . Enriched targets.

RAPID COMMUNICATION

Symmetry coefficient and the isospin-spin dependence of the single-particle potential

K. M. Khanna and P. K. Barhai

Phys. Rev. C 11, 264(R) (1975) - Published 1 January, 1975

Show Abstract

The symmetry coefficient $a_{τ}$ for nuclear matter with a given neutron excess has been calculated within the framework of the independent particle model using two effective interactions determined in an earlier paper. The interactions referred to as Set 1 and Set 2 have been found to give $a_{τ} = 44.89$ MeV and $a_{τ} = 43.16$ MeV, respectively. The isospin-spin dependent part of the single-particle potential $U_{1}$ has also been estimated using an explicit expression due to Brueckner and Dabrowski. The corresponding values of $U_{1} (k_{F})$ are 158.48 and 102.64 MeV for the interactions of Set 1 and Set 2, respectively. These values of $a_{τ}$ and $U_{1} (k_{F})$ compare reasonably well with those obtained by others.

RAPID COMMUNICATION

Negative pion capture in ${}^{3}{He}$

J. McCarthy, T. Meyer, R. C. Minehart, E. A. Wadlinger, K. O. H. Ziock, and J. Vincent

Phys. Rev. C 11, 266(R) (1975) - Published 1 January, 1975

Show Abstract

RAPID COMMUNICATION

Coriolis perturbation effects for $K = \frac{3}{2}$ rotational bands in odd-proton rare-earth nuclei

P. C. Joshi and P. C. Sood

Phys. Rev. C 11, 269(R) (1975) - Published 1 January, 1975

Show Abstract

The evidence for the rotation-particle coupling effect in $K = \frac{3}{2}$ band levels in odd-proton rare-earth nuclei is examined. Empirical analysis establishes the presence of an alternating term in the rotational energy expression and phenomenological fits to the observed energies result in an evaluation of the coefficient of the alternating energy term. Interpretation of this coefficient as arising from the perturbation treatment of the Coriolis interaction term is examined through theoretical calculation employing the usual Nilsson model potential. The effect of the variation of the potential parameters and the introduction of a deformation in the spin-orbit term are studied. The results are compared with those obtained in an earlier similar study of the odd-neutron rare-earth nuclei.

NUCLEAR STRUCTURE Odd- $Z$ even- $N$ rare earth nuclei, calculated Coriolis perturbation effects to $K = \frac{3}{2}$ rotational band levels.

RAPID COMMUNICATION

Relativistic and retardation effects in the Thomas-Reiche-Kuhn sum rule for a bound particle

J. L. Friar and S. Fallieros

Phys. Rev. C 11, 274(R) (1975) - Published 1 January, 1975

Show Abstract

Relativistic and retardation corrections of lowest order are evaluated for the photoabsorption Thomas-Reiche-Kuhn (TRK) sum rule of a particle bound in a potential. It is found that the retardation corrections partially cancel and the remainder is canceled by part of the relativistic corrections. The latter corrections depend on the Lorentz-transformation properties of the potential. The complete integrated photoabsorption cross section including first-order relativistic corrections, is found to be equal to the high-energy limit of the Compton amplitude calculated by Goldberger and Low, a result which is the dispersion-relation form of the TRK sum rule. A heuristic derivation of the latter results is presented.

RAPID COMMUNICATION

Nonrelativistic Compton amplitude

J. L. Friar and S. Fallieros

Phys. Rev. C 11, 277(R) (1975) - Published 1 January, 1975

Show Abstract

A simple heuristic argument is made which demonstrates the nonanalyticity of the nonrelativistic and semirelativistic forward Compton amplitudes for photon scattering from a bound particle. Hence, no dispersion relation can be written. The "no-retardation" theorem of Gerasimov is thus shown to be incorrect. A variety of topics associated with this problem are discussed.

RAPID COMMUNICATION

Consistency of the recoil-distance method and the Doppler-shift attenuation method for lifetime measurements using titanium as the slowing-down environment

B. Haas, J. Chevallier, N. Schulz, J. Styczen, and M. Toulemonde

Phys. Rev. C 11, 280(R) (1975) - Published 1 January, 1975

Show Abstract

A coincidence recoil-distance Doppler-shift method has been used to obtain lifetimes for the 748 keV, ${\frac{3}{2}}^{+}$ , 7.7±0.9 ps and 1022 keV, ${\frac{11}{2}}^{-}$ , 4.5±1.3 ps levels in ${}^{49}V$ . A comparison with lifetime values determined by the Doppler-shift attenuation method shows good agreement.

NUCLEAR REACTIONS ${}^{46}{Ti} (α, p γ)$ , $E = 10$ MeV; measured recoil distance. ${}^{49}V$ levels deduced $τ$ . Enriched target.

Select page:

Physical Review C

Recent Articles

Filter

Recent Issues

Energy dependence of the ( $p, n$ ) analog cross sections of the molybdenum isotopes between 16 and 26 MeV

Coulomb excitation of levels in ${}^{95}{Mo}$ and ${}^{97}{Mo}$

Rotational band structure in $N = 105 and 107$ isotones: I. Evidence for the transition to $| I Rj 〉$ coupling at high spins in ${}^{179}W$

Structure of ${}^{20}{Ne}$ : The ${}^{19}F ({}^{3}{He}, d) {}^{20}{Ne}$ reaction

Matter radii of the even tin isotopes from elastic $α$ and ${}^{16}O$ scattering

Double $K$ -shell ionization in the internal-conversion decay of ${}^{109}{Ag}^{m}$

Microscopic study of the variable-moment-of-inertia model for rare-earth nuclei

Quadrupole variation of projected spectra of even Ti isotopes

Matrix solution of the Bethe-Faddeev equations

Nuclear $g$ factors of the ${\frac{21}{2}}^{-}$ and the ${\frac{29}{2}}^{+}$ states in ${}^{211}{At}$

Energy dependence of isospin mixing matrix elements

Magnetic moment of the deuteron and phenomenological models of the nucleon-nucleon interaction

Rule for the spins of the lowest state with $T = | T_{Z} |$ of doubly odd nuclei having $j^{n}$ configuration

Coulomb-nuclear interference for the ( $d, d^{'}$ ) reaction on isotopes of Nd

Symmetry coefficient and the isospin-spin dependence of the single-particle potential

Negative pion capture in ${}^{3}{He}$

Coriolis perturbation effects for $K = \frac{3}{2}$ rotational bands in odd-proton rare-earth nuclei

Relativistic and retardation effects in the Thomas-Reiche-Kuhn sum rule for a bound particle

Nonrelativistic Compton amplitude

Consistency of the recoil-distance method and the Doppler-shift attenuation method for lifetime measurements using titanium as the slowing-down environment

Filter

Recent Issues

Filter

Article Lookup

Enter a citation