Recent Articles

Inclusive breakup reactions

N. Austern and C. M. Vincent

Phys. Rev. C 23, 1847 (1981) - Published 1 May, 1981

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Inclusive breakup reactions of the type $d + A \to p + anything$ require sums over excited states of the unobserved $n + A$ system. We show that the summed distorted-wave Born approximation cross section can be expressed in closed form as an elastic distorted-waves expectation of an optical model propagator for the unobserved system. The contribution of fluctuations to the energy-averaged cross section is automatically contained in the derived identity. Previous results can be recovered from this identity if corresponding surface approximations are introduced. A new approximation simplifies the identity by omitting the imaginary part of the optical potential. This approximation selects the energy-shell part of the propagator and reduces the inclusive cross section to the same form obtained for the ground state reaction $A (d, p n) A$ , with a modified (real) optical potential for the unobserved neutron.

NUCLEAR REACTIONS Scattering theory, closed form sum rule for inclusive breakup, DWBA, approximations extracted.

Neutron-deuteron scattering at zero energy with realistic nucleon-nucleon interactions

J. J. Benayoun, C. Gignoux, and J. Chauvin

Phys. Rev. C 23, 1854 (1981) - Published 1 May, 1981

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An exact method to obtain the wave function of the neutron-deuteron system at energies below the breakup threshold is presented. The scattering length and the effective range are calculated in the case of three local potentials. The quantity $k cot δ$ as a function of energy is given for one of these interactions. As for the triton case, realistic potentials are unable to cope completely with experimental data.

NUCLEAR REACTIONS $d (n, n) d$ , $E = 0$ MeV (cold neutrons); calculated scattering length and effective range; wave function also obtained.

${}^{12}C (p, p^{'}) {}^{12}C$ reaction at 155 and 200 MeV and precritical phenomena

J. R. Comfort, R. E. Segel, G. L. Moake, D. W. Miller, and W. G. Love

Phys. Rev. C 23, 1858 (1981) - Published 1 May, 1981

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Cross-section and analyzing-power data are presented for the ${}^{12}C (p, p^{'}) {}^{12}C$ reaction at bombarding energies of 155 and 200 MeV. Comparisons are made with the systematics of data from other energies. Distorted-wave impulse-approximation calculations for the "pion-like" $1^{+}$ , $T = 1$ transition to the 15.11-MeV state are successful for $q < 280$ MeV/c, but are substantially smaller than the data at larger momentum transfers. The implications of the data regarding precritical behavior associated with the pion-condensation threshold are discussed.

NUCLEAR REACTIONS ${}^{12}C (p, p^{'})$ , $E = 155$ MeV, measured $σ (E, θ)$ ; $E = 200$ MeV, measured $σ (E, θ)$ , $A_{y} (θ)$ ; $θ = 6 - 50 °$ , $Δ θ = 2 - 3 °$ , $E_{x} = 11 - 17$ MeV. DWIA analysis. Precritical phenomena near pion-condensation threshhold.

Cross sections relevant to gamma-ray astronomy: Proton induced reactions

P. Dyer, D. Bodansky, A. G. Seamster, E. B. Norman, and D. R. Maxson

Phys. Rev. C 23, 1865 (1981) - Published 1 May, 1981

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Gamma-ray production cross sections have been measured for the gamma-ray lines most strongly excited in the proton bombardment of ${}^{12}C$ , ${}^{14}N$ , ${}^{16}O$ , ${}^{20}{Ne}$ , ${}^{24}{Mg}$ , ${}^{28}{Si}$ , and ${}^{56}{Fe}$ , for proton energies from threshold to 23 MeV. In addition, cross sections for the ${}^{14}N (p, n) {}^{14}O$ and ${}^{56}{Fe} (p, n) {}^{56}{Co}$ reactions were determined from delayed gamma-ray yields. Ge(Li) detectors were used. Tabulations of cross sections averaged over proton energy bins of 1 MeV and over power law distributions in proton energy are provided for calculations relevant to gamma-ray line astronomy. Examples are given of astrophysical information which might be extracted from spectra acquired with gamma-ray spectrometers in space, using these cross sections, e.g., parameters describing the energy distribution of incident protons.

NUCLEAR REACTIONS $p + {}^{12}C$ , ${}^{14}N$ , ${}^{16}O$ , ${}^{20}{Ne}$ , ${}^{24}{Mg}$ , ${}^{28}{Si}$ , ${}^{56}{Fe}$ ; ${}^{14}N (p, n)$ , ${}^{56}{Fe} (p, n)$ . $E = threshold to 23$ MeV. Measured $γ$ production cross sections. Applications to $γ$ line astronomy.

States in ${}^{14}C$ from $σ_{T}$ and $σ_{el} (θ)$ for ${}^{13}C + n$ : Measurement, $R$ -matrix analysis, and model calculations

R. O. Lane, H. D. Knox, P. Hoffmann-Pinther, R. M. White, and G. F. Auchampaugh

Phys. Rev. C 23, 1883 (1981) - Published 1 May, 1981

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Differential elastic scattering cross sections for neutrons scattered from ${}^{13}C$ have been measured at 9 angles from 20° to 160° for $1.25 MeV \leq E_{n} \leq 6.5 MeV$ MeV. These data together with high-resolution total cross section measurements were analyzed by means of a multichannel-multilevel $R$ -matrix program to determine $J$ , $π$ , $γ_{λ c}$ , and other parameters of many newly assigned states up to $E_{x} = 14$ MeV in ${}^{14}C$ . This extensive and in-depth investigation of ${}^{14}C$ provided a basis for comparison to nuclear model predictions over a wide range of excitation energy. A core-coupling model was employed to calculate states in ${}^{14}C$ as well as nucleon spectroscopic factors for reactions leading to these states. Calculations of states in ${}^{14}C$ via both effective interactions and a weak coupling model, together with those from the core-coupling model, were compared to results of the $R$ -matrix analysis. Much of the structure observed in the experimental work is predicted by the models.

NUCLEAR REACTIONS ${}^{13}C (n, n) {}^{13}C$ , $1.25 <~ E_{n} <~ 6.5$ MeV, measured $σ (θ)$ , $R$ -matrix analysis, ${}^{14}C$ deduced $J^{π}$ , $γ_{λ c}$ .

NUCLEAR STRUCTURE ${}^{14}C$ , calculated negative parity states, core coupling. Comparison to other models.

$0_{1}^{+}$ → $0_{2}^{+}$ inelastic form factor of ${}^{16}O$

D. A. Agrello and O. Portilho

Phys. Rev. C 23, 1898 (1981) - Published 1 May, 1981

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We calculate the $0_{1}^{+}$ → $0_{2}^{+}$ inelastic form factor of ${}^{16}O$ in the alpha-particle model and study the influence of a three-body potential on it.

NUCLEAR REACTIONS ${}^{16}O (e, e)$ ; calculated inelastic form factor. Variational calculation, harmonic oscillator wave functions. $4 - α$ model. Influence of three-body potential.

Analog of the 3.00-MeV state of ${}^{32}P$ in ${}^{32}S$

R. Hentelä

Phys. Rev. C 23, 1900 (1981) - Published 1 May, 1981

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The analog of the $E_{x} = 3005$ -keV, $J^{π} = 3^{+}$ state of ${}^{32}P$ in ${}^{32}S$ has been studied using the ${}^{31}P (p, γ) {}^{32}S$ reaction. The analog candidate at $E_{p} = 1151$ keV, $E_{x} = 9979$ keV, previously regarded as a singlet, has been established to be a doublet with 0.5 keV spacing. The gamma decay schemes, the branching ratios, and the resonance strengths of the members of the doublet have been determined. The results of the angular distribution measurements together with earlier data lead to unique spin and parity assignments of $4^{-}$ and $3^{+}$ , respectively, for the lower and upper members of the doublet. In addition, for the bound states of ${}^{32}S$ at $E_{x} = 6852 and 7485$ keV, unique assignments of $J^{π} = 4^{+} and 2^{+}$ , respectively, have been deduced.

NUCLEAR REACTIONS ${}^{31}P (p, γ)$ , $E_{p} = 1.15$ MeV; measured $σ (E_{p}, E_{γ}, θ)$ . ${}^{32}S$ levels deduced resonance strengths, $γ$ -ray branching ratios, $J$ , $π$ , mixing ratios. Ge(Li) detectors, natural targets.

Reaction mechanism of ( $α, d$ ) transfer in ${}^{208}{Pb} (α, d) {}^{210}{Bi}$ at 33 and 48 MeV

W. W. Daehnick, M. J. Spisak, and J. R. Comfort

Phys. Rev. C 23, 1906 (1981) - Published 1 May, 1981

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The reaction ${}^{208}{Pb} (α, d) {}^{210}{Bi}$ has been studied at 33 and 48 MeV with particular emphasis on the ( $h_{\frac{9}{2}} g_{\frac{9}{2}}$ ) ground-state multiplet and the high-spin members of other low-lying $n - p$ multiplets, which are expected to be of high purity. About 50 angular distributions were obtained and used as a basis for a study of the transfer mechanism in ( $α, d$ ) reactions. The analysis was made with the microscopic distorted-wave Born approximation and with two-step coupled-reaction-channel calculations. The $L$ transfers observed ranged from $L = 1$ to $L = 13$ and were consistent with one-step transfer selection rules. Nevertheless, the relative magnitudes of cross sections to levels of the ( $h_{\frac{9}{2}} g_{\frac{9}{2}}$ ) ground-state multiplet disagree with one-step-transfer predictions at either beam energy by factors which vary from 0.5 to 4.0. This phenomenon is explained as a coherent addition of the sequential stripping amplitudes ( $α, t; t, d$ ) and ( $α, {}^{3}{He}; {}^{3}{He}, d$ ) to the one-step amplitude, where the important ( $α, t; t, d$ ) amplitude typically amounts to about 50% of the one-step ( $α, d$ ) amplitude for high- and low-spin states alike. Details of the coupled-reaction-channel analysis are provided. The two-step calculations were kept free of arbitrary parameters by a simultaneous analysis of previously published ${}^{208}{Pb} (t, d)$ , ${}^{208}{Pb} ({}^{3}{He}, d)$ , ${}^{208}{Pb} (α, t)$ , and ${}^{208}{Pb} (α, {}^{3}{He})$ single-particle transfer data. This systematic reanalysis indicated again that most single-particle states in ${}^{209}{Pb}$ and ${}^{209}{Bi}$ show their full spectroscopic strength, but that the $π i_{\frac{13}{2}}$ and $ν j_{\frac{15}{2}}$ single-particle states are not pure and have single-nucleon spectroscopic factors of about 0.75±0.10.

NUCLEAR REACTIONS ${}^{208}{Pb} (α, d) {}^{210}{Bi}$ , $E_{α} = 33 and 48$ MeV, measured $E_{d}$ and $σ (θ, E_{d})$ with QDDD spectrograph. DWBA and CRC analysis, deduced levels, $L_{α, d}$ , evidence for sequential stripping.

Reduced $M 1$ , $E 1$ , $E 2$ , and $E 3$ transition probabilities for transitions in ${}^{156 - 160}{Gd}$ and ${}^{160 - 164}{Dy}$

F. K. McGowan and W. T. Milner

Phys. Rev. C 23, 1926 (1981) - Published 1 May, 1981

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Direct $E 2$ and $E 3$ Coulomb excitation of $2^{+}$ and $3^{-}$ states with 13.5-MeV ${}^{4}{He}$ ions on isotopically enriched targets of ${}^{156 - 160}{Gd}$ and ${}^{160 - 164}{Dy}$ has been measured by means of $γ$ -ray spectroscopy. Vibrational-like $2^{+}$ and $3^{-}$ states were identified in each nucleus. The $B (E λ, 0 \to J = π)$ is obtained for excitation of each state, and information is given on the reduced transition probabilities for the different decay modes of these states. The experimental results are compared with theoretical predictions of nuclear models describing these states. A reasonable account of the reduced $E 2$ transition probabilities is provided by the interacting boson model.

NUCLEAR REACTIONS ${}^{156 - 160}{Gd} (α, α^{'} γ)$ , ${}^{160 - 164}{Dy} (α, α^{'} γ)$ , $E = 13.5$ MeV; measured $I_{γ}$ , $E_{γ}$ , $γ (θ)$ , Doppler broadening. ${}^{156 - 160}{Gd}$ , ${}^{160 - 164}{Dy}$ levels deduced $B (E 2)$ , $B (M 1)$ , $B (E 3)$ , $B (E 1)$ , $T_{\frac{1}{2}} (3^{-})$ , $J^{π}$ , $δ$ . Enriched targets.

Positive- and negative-parity level structures of ${}^{194}{Pt}$ from $n, n^{'} γ$ reaction spectroscopy

A. J. Eilo, S. W. Yates, D. F. Coope, J. L. Weil, and M. T. McEllistrem

Phys. Rev. C 23, 1938 (1981) - Published 1 May, 1981

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Energy levels of ${}^{194}{Pt}$ populated by the ( $n, n^{'} γ$ ) reaction have been studied at incident neutron energies up to 4.5 MeV. Detailed $γ$ -ray excitation functions were measured between 1.4 and 2.5 MeV, and $γ$ -ray angular distributions were obtained at 2.5 MeV. Essentially all previously known levels below 2.0 MeV having $J \leq 6$ were observed. New level placements and spins for some previously unassigned levels have been deduced. The negative-parity states with spins from $1^{-}$ to $6^{-}$ are interpreted in terms of the semi-decoupled model. The positive-parity states are compared to several models, including the boson expansion theory and the interacting boson model. The interacting boson model adequately accounts for the observed branching ratios, with the exception of the previously noted anomalous 1547-keV $0^{+}$ state. The boson expansion theory enjoys comparable success for ${}^{194}{Pt}$ .

NUCLEAR REACTIONS ${}^{194}{Pt} (n, n^{'} γ)$ , $E_{n} = 1.2 - 4.5$ MeV. Measured $E_{γ}$ , $I_{γ}$ , $σ (E, E_{γ}, θ_{γ})$ , ${}^{194}{Pt}$ deduced levels, branching ratios, $J$ , $π$ . Compared levels and branching ratios to theory. Enriched target, Ge(Li) detector, time-of-flight background suppression.

Dirac optical model analysis of $\vec{p} - {}^{40}{Ca}$ elastic scattering at 180 MeV and the wine-bottle-bottom shape

L. G. Arnold, B. C. Clark, R. L. Mercer, and P. Schwandt

Phys. Rev. C 23, 1949 (1981) - Published 1 May, 1981

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A Dirac equation optical model calculation with the real part of the optical potential constrained by relativistic model considerations is used to represent 180 MeV $\vec{p} - {}^{40}{Ca}$ elastic scattering data. The Dirac equation optical potential consists of a mixture of Lorentz scalar and Lorentz vector potentials. Features of an effective Schrödinger equation optical potential constructed from these two potentials are deduced and compared with results from the standard optical model.

NUCLEAR REACTIONS Relativistic optical model; ${}^{40}{Ca} (p, p)$ , $T_{p} = 181$ MeV, calculated $σ (θ)$ and $A (θ)$ ; deduced effective optical potential.

Core excitations in ${}^{63}{Cu}$ by the ${}^{63}{Cu} (p, p^{'}) {}^{63}{Cu}$ and ${}^{65}{Cu} (p, t) {}^{63}{Cu}$ reactions

Y. Iwasaki, G. M. Crawley, and J. E. Finck

Phys. Rev. C 23, 1960 (1981) - Published 1 May, 1981

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Core excitations up to $E_{x} = 4$ MeV in ${}^{63}{Cu}$ have been studied by the reactions ${}^{63}{Cu} (p, p^{'}) {}^{63}{Cu}$ and ${}^{65}{Cu} (p, t) {}^{63}{Cu}$ at 40 MeV proton energy. The transferred angular momentum $L$ has been determined for each transition on the basis of the angular distribution shape. A quarter-plus-doublet pattern is consistently observed for the groups of states corresponding to the $2_{1}^{+}$ , $3_{1}^{-}$ , and $4_{1}^{+}$ states of the core nucleus ${}^{62}{Ni}$ . This implies the existence of doublets arising from the coupling of collective states of the core with the $2 p_{\frac{1}{2}}$ proton orbital, in addition to the quartets from the coupling with the $2 p_{\frac{3}{2}}$ proton orbital considered in the conventional weak-coupling excited-core model. It is pointed out that the existence of a weak-coupling situation cannot be proved only on the basis of transfer-reaction data, and in this regard the importance of a comparative study of the inelastic-scattering and transfer-reaction data is emphasized.

NUCLEAR REACTIONS ${}^{65}{Cu} (p, t) {}^{63}{Cu}$ and ${}^{63}{Cu} (p, p^{'}) {}^{63}{Cu}$ , $E = 40$ MeV; measured $E_{x}$ and $σ (θ)$ , determined $L$ . Resolution 16 keV for the ( $p, t$ ), 20 keV for the ( $p, p^{'}$ ). Enriched targets. Deduced excited-core multiplets.

Enhanced primary dipole transitions in the ${}^{89}Y (n, γ)$ reaction

S. Raman, O. Shahal, A. Z. Hussein, G. G. Slaughter, and J. A. Harvey

Phys. Rev. C 23, 1979 (1981) - Published 1 May, 1981

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Neutron capture $γ$ rays from a ${}^{89}Y$ target have been studied for several resonances below 6 keV neutron energy employing a Ge(Li) detector and time-of-flight techniques. The primary $M 1$ and $E 1$ transitions leading to low-lying states in ${}^{90}Y$ show some enhancements. The 3.38-keV resonance (suggested previously as $s$ wave on the basis of the smallness of the total radiation width) is definitely shown to be a $p$ -wave resonance through neutron transmission measurements.

NUCLEAR REACTIONS ${}^{89}Y (n, γ)$ , $E_{n} = 1 - 6$ keV, measured $E_{γ}$ , $I_{γ}$ ; ${}^{89}Y (n)$ , $E_{n} = 1 - 10$ keV, measured total $σ (E)$ . ${}^{90}Y$ deduced resonances, resonance parameters, levels, neutron separation energy. Ge(Li) detector.

Behavior of coupled-channel wave functions in the centrifugally dominated region of the $l - r$ plane

W. J. G. Thijssen, B. J. Verhaar, and A. M. Schulte

Phys. Rev. C 23, 1984 (1981) - Published 1 May, 1981

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A simple three-channel model with one radial coupling point is introduced to study the interplay between channel coupling and barrier penetration in inelastic scattering. The results are generalized to realistic coupled-channel calculations by studying the differential equations satisfied by matrices $a$ and $c$ defined in terms of a "mathematical" solution matrix. Properties of $a$ and $c$ suggested by these equations are confirmed by realistic calculations for rotational excitation of a deformed nucleus. A different sensitivity of $S$ -matrix elements to linear dependence effects is indicated for high- $l$ to low- $l$ transitions as compared to the inverse transitions. An explanation is presented, as well as an application. An extended three-channel model including a second coupling point is used to study the influence of channel truncation.

NUCLEAR REACTIONS Scattering theory, channel coupling in classically inaccessible region of $l - r$ plane.

Collective states in ${}^{198}{Pt}$ and models for shape transitional nuclei

S. W. Yates, A. Khan, M. C. Mirzaa, and M. T. McEllistrem

Phys. Rev. C 23, 1993 (1981) - Published 1 May, 1981

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Studies of the ( $n, n^{'}$ ) and ( $n, n^{'} γ$ ) reactions, together with other recent data, delineate the level and decay schemes for collective levels of ${}^{198}{Pt}$ below 1.5 MeV excitation energy. The level scheme, which approximates that of an anharmonic vibrator, is consistent with boson expansion theory calculations. These calculations place ${}^{198}{Pt}$ naturally in a systematic development of nuclear structure through the Pt isotopes and explain the $γ$ -ray decay intensities of excited levels. The O(6) limit of the interacting boson model, on the other hand, appears inappropriate for ${}^{198}{Pt .}$

NUCLEAR REACTIONS ${}^{198}{Pt} (n, n^{'} γ)$ , $E_{n} = 0.8 - 2.5$ MeV, ${}^{198}{Pt} (n, n^{'})$ . $E_{n} = 1.68$ MeV; measured $E_{γ}$ , $I_{γ}$ , $σ (E; E_{γ}, 125 °)$ , $σ (E_{γ}, θ_{γ})$ , $σ (E_{n}, θ)$ . Deduced levels, $J$ , $π$ . Compared to boson expansion theory and interacting boson model. Enriched target, time-of-flight neutron detection.

Systematics of the giant monopole resonance from inelastic alpha scattering

D. H. Youngblood, P. Bogucki, J. D. Bronson, U. Garg, Y. -W. Lui, and C. M. Rozsa

Phys. Rev. C 23, 1997 (1981) - Published 1 May, 1981

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The properties of the isoscalar giant monopole resonance have been studied with inelastic $α$ scattering between $0 ° \leq θ_{L} \leq 8 °$ , where the quadrupole and monopole states can be distinguished by their angular distributions. Data were taken for ${}^{12}C$ , ${}^{27}{Al}$ , ${}^{40}{Ca}$ , ${}^{48}{Ti}$ , ${}^{58}{Ni}$ , ${}^{64, 66}{Zn}$ , ${}^{90}{Zr}$ , ${}^{116, 118, 120, 124}{Sn}$ , ${}^{144, 154}{Sm}$ , and ${}^{208}{Pb}$ mostly at $E_{α} = 129$ MeV; some data were taken at $E_{α} = 99$ MeV and $E_{α} = 117$ MeV. A monopole resonance was identified in all the nuclei with $A \geq 64$ at $E_{x} \approx \frac{76}{A^{\frac{1}{3}}}$ MeV. In nuclei with $A \geq 90$ , most of the energy weighted sum rule was located in this state; in ${}^{64, 66}{Zn}$ , less than one-third of the energy weighted sum rule was located. No evidence for a monopole resonance was found in nuclei with $A \leq 58$ .

NUCLEAR REACTIONS ${}^{12}C$ , ${}^{27}{Al}$ , ${}^{40}{Ca}$ , ${}^{48}{Ti}$ , ${}^{58}{Ni}$ , ${}^{64, 66}{Zn}$ , ${}^{90}{Zr}$ , ${}^{116, 118, 120, 124}{Sn}$ , ${}^{144, 154}{Sm}$ , ${}^{208}{Pb} (α, α^{'})$ ; $E_{α} = 99, 117, 129$ MeV. Measured $E_{x}$ , $σ (θ)$ , giant resonances; deduced $L$ , nuclear incompressibility.

$γ$ decay and lifetimes of excited levels in ${}^{49}{Ti}$

P. A. Mandò, G. Poggi, P. Sona, and N. Taccetti

Phys. Rev. C 23, 2008 (1981) - Published 1 May, 1981

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The decay scheme of ${}^{49}{Ti}$ up to 5.2 MeV excitation energy was investigated by the ( $d, p γ$ ) and ( $p, p^{'} γ$ ) reactions and by Coulomb excitation. Singles spectra and $p - γ$ coincidences were recorded. Lifetimes or lifetime limits were determined for 15 levels by Coulomb excitation or by the Doppler shift attenuation method. A consistent decay scheme for levels up to $E_{x} = 5.2$ MeV was deduced including many so far unobserved transitions. On the basis of these results $J^{π}$ assignments are proposed and a comparison is made with the predictions of the deformed configuration mixing model.

NUCLEAR REACTIONS ${}^{48}{Ti} (d, p γ)$ , ${}^{49}{Ti} (p, p^{'} γ)$ , Coulomb excitation by alpha bombardment. $E_{d} = 6$ MeV, $E_{p} = 6$ MeV, $E_{α} = 5.25 - 5.8$ MeV. Enriched ${}^{49}{Ti}$ target. $p - γ$ coincidences. Doppler shift attenuation. Measured level energies, decay scheme, lifetimes.

Structure of low-lying states in ${}^{94}{Mo}$

E. Adamides, L. D. Skouras, and A. C. Xenoulis

Phys. Rev. C 23, 2016 (1981) - Published 1 May, 1981

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The ( $p, p^{'} γ$ ) reaction has been used to investigate the structure of low-lying states in ${}^{94}{Mo}$ . Single directional correlations provided reliable branching ratios, $J^{π}$ assignments, and multipole mixing ratios from analysis of the correlations via the compound statistical theory for nuclear reactions. From these measurements the $J^{π}$ value of the 2067.1 keV level was definitely assigned as $2^{+}$ . Lifetimes for two states in ${}^{94}{Mo}$ and limits for two additional states were obtained by the Doppler-shift-attenuation method. Values of $B (M 1)$ and $B (E 2)$ were obtained for six transitions in ${}^{94}{Mo}$ . Futhermore, properties of low-lying states in ${}^{94}{Mo}$ were calculated in the shell-model framework and are compared with the corresponding experimental quantities.

NUCLEAR REACTIONS ${}^{94}{Mo} (p, p^{'} γ)$ , $E_{p} = 4.8 and 5.0$ MeV, enriched targets. Measured $E_{γ}$ , $I_{γ} (ϑ)$ , $Δ E_{γ} (τ)$ , deduced ${}^{94}{Mo}$ levels, branching ratios, $τ$ , $δ (\frac{E 2}{M 1})$ , $B (E 2)$ , $B (M 1)$ ; Ge(Li) detectors. Calculated ${}^{94}{Mo}$ positive-parity levels, $B (E 2)$ , $B (M 1)$ , $τ$ , branching ratios.

High spin states in ${}^{74}{Br}$

G. Garcia Bermudez, A. Filevich, A. J. Kreiner, M. A. J. Mariscotti, C. Baktash, E. der Mateosian, and P. Thieberger

Phys. Rev. C 23, 2024 (1981) - Published 1 May, 1981

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States of ${}^{74}{Br}$ excited through the ${}^{60}{Ni} ({}^{16}O, n p)$ reaction at $E = 40 to 55$ MeV were studied. From the excitation function, $γ$ -ray angular distribution, $γ - γ$ coincidences, and decay measurements three groups of $γ$ rays depopulating states with probable spin values ranging up to $I = (11)$ were found. A half-life of 49.5 min and $I = (4)$ for the high spin isomeric state at $E \approx 200$ keV were determined at variance with previous values of 41.5 min and $I = (4^{-})$ . The group of $γ$ rays feeding the $I = (4)$ isomer shows similarities with a recently reported band built on a $4^{+}$ isomer in both ${}^{76}{Br}$ and ${}^{78}{Br}$ . The interpretation of these states as members of the $\tilde{π} g_{\frac{9}{2}} \otimes \tilde{ν} g_{\frac{9}{2}}$ structure is discussed.

NUCLEAR REACTIONS ${}^{60}{Ni} ({}^{16}O, n p γ) {}^{74}{Br}$ , $E = 40 - 55$ MeV. Measured $E_{γ}$ , $I_{γ}$ , $I_{γ} (t)$ , $I_{γ} (θ)$ , $γ - γ (t)$ . ${}^{74}{Br}$ deduced levels, $I^{π}$ . Enriched Ni target. Ge(Li) detectors.

Correlated structures in the ${}^{14}N$ + ${}^{12}C$ reaction

K. R. Cordell, C. -A. Wiedner, and S. T. Thornton

Phys. Rev. C 23, 2035 (1981) - Published 1 May, 1981

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The exit channels for elastic and alpha particles have been detected for ${}^{14}N$ bombardment on ${}^{12}C$ over the energy range $E_{lab} = 45 - 60.0$ MeV. Extensive statistical analyses of the data show evidence for nonstatistical structure (or "resonances"). Some of these structures are correlated in the two exit channels, especially one prominent structure at $E_{c . m} = 22.4$ MeV. The reaction mechanism is discussed, and all the evidence is consistent with a quasimolecular resonance formed by the ${}^{14}N$ and ${}^{12}C$ entrance channel nuclei.

NUCLEAR REACTIONS ${}^{12}C$ ( ${}^{14}N$ , ${}^{14}N$ ), ( ${}^{14}N$ , ${}^{12}C$ ), ( ${}^{14}N, α$ ), $E = 45.0 - 60.0$ MeV; measured $σ (E)$ at $θ_{lab} = 8 °$ for $α$ and $σ (E)$ at $θ_{lab} = 15 °, 30 °$ for ${}^{14}N$ , ${}^{12}C$ ; statistical and Hauser-Feshbach analysis. Natural target. Resolution 130 keV for $α$ , 400-700 keV for ${}^{14}N$ , ${}^{12}C$ . Discussion of reaction mechanism.

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Physical Review C

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Inclusive breakup reactions

Neutron-deuteron scattering at zero energy with realistic nucleon-nucleon interactions

${}^{12}C (p, p^{'}) {}^{12}C$ reaction at 155 and 200 MeV and precritical phenomena

Cross sections relevant to gamma-ray astronomy: Proton induced reactions

States in ${}^{14}C$ from $σ_{T}$ and $σ_{el} (θ)$ for ${}^{13}C + n$ : Measurement, $R$ -matrix analysis, and model calculations

$0_{1}^{+}$ → $0_{2}^{+}$ inelastic form factor of ${}^{16}O$

Analog of the 3.00-MeV state of ${}^{32}P$ in ${}^{32}S$

Reaction mechanism of ( $α, d$ ) transfer in ${}^{208}{Pb} (α, d) {}^{210}{Bi}$ at 33 and 48 MeV

Reduced $M 1$ , $E 1$ , $E 2$ , and $E 3$ transition probabilities for transitions in ${}^{156 - 160}{Gd}$ and ${}^{160 - 164}{Dy}$

Positive- and negative-parity level structures of ${}^{194}{Pt}$ from $n, n^{'} γ$ reaction spectroscopy

Dirac optical model analysis of $\vec{p} - {}^{40}{Ca}$ elastic scattering at 180 MeV and the wine-bottle-bottom shape

Core excitations in ${}^{63}{Cu}$ by the ${}^{63}{Cu} (p, p^{'}) {}^{63}{Cu}$ and ${}^{65}{Cu} (p, t) {}^{63}{Cu}$ reactions

Enhanced primary dipole transitions in the ${}^{89}Y (n, γ)$ reaction

Behavior of coupled-channel wave functions in the centrifugally dominated region of the $l - r$ plane

Collective states in ${}^{198}{Pt}$ and models for shape transitional nuclei

Systematics of the giant monopole resonance from inelastic alpha scattering

$γ$ decay and lifetimes of excited levels in ${}^{49}{Ti}$

Structure of low-lying states in ${}^{94}{Mo}$

High spin states in ${}^{74}{Br}$

Correlated structures in the ${}^{14}N$ + ${}^{12}C$ reaction

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