Gyromagnetic ratios of excited states in 107, 109Ag

The gyromagnetic ratios of the lowest excited $\text{3}\text{2}{}^{\mathrm{?}}\text{and}\text{5}\text{2}{}^{\mathrm{?}}$ states in ^{107, 109}Ag were simultaneously measured relative to that of the 2₁⁺ level in ¹⁰⁸Pd. The thin-foil, perturbed γ-ray angular distribution technique was employed utilizing the transient hyperfine magnetic field present at the nuclei of these ions as they swiftly recoiled through a thin magnetized Co foil. The states of interest were Coulomb-excited using beams of 100 MeV ³²S ions. The present measurements yielded $\text{g(}\text{3}\text{2}{}^{\mathrm{?}}\text{;}{}^{107}\text{Ag}\text{) = +0.63 ± 0.09, g(}\text{5}\text{2}{}^{\mathrm{?}}\text{;}{}^{107}\text{Ag}\text{) = + 0.37±0.06, g(}\text{3}\text{2}{}^{\mathrm{?}}\text{;}{}^{109}\text{Ag}\text{) = +0.77 ± 0.10,}\text{and}\text{g(}\text{5}\text{2}{}^{\mathrm{?}}\text{;}{}^{109}\text{Ag}\text{) = +0.36 ± 0.05}$. These findings are compared with weak-coupling and other appropriate model calculations.     

Coulomb excitation and lifetime measurements of the 21+ states in 76, 82, 84Kr

A mean lifetime of τ = 35 ± 3 ps of the 2⁺₁ state in ⁷⁶Kr has been measured with the recoil distance method via the reaction ⁶³Cu(¹⁹F, α2n)⁷⁶Kr. The B(E2; 0⁺₁ → 2⁺₁) values and lifetimes of the 2⁺₁ states in ^{82, 84}Kr have been measured via Coulomb excitation using the 1.4 MeV/A UNILAC krypton beams. The intensities of the γ-rays from the Coulomb excited levels of ^{82, 84}Kr were interrelated with those of the target nuclei ²⁷Al, ^{64, 66}Zn and ^{70, 72, 74, 76}Ge and yielded the values $\text{B(}\text{E}\text{2; 0}{}^{\mathrm{+}}{}_1\text{→ 2}{}^{\mathrm{+}}{}_1\text{= 0.255±0.009}\text{and}\text{0.122 ± 0.005}\text{e}\text{2 ·}\text{b}\text{2}\text{for}{}^{\mathrm{82,\; 84}}\text{Kr}$, respectively. In turn, these B(E2) values and the (E2; 0⁺₁ → 2⁺₁ values of the even Ge and Zn isotopes from the literature were used in a Doppler-shift attenuation analysis to obtain experimentally lacking electronic stopping power for Kr ions slowing down in Al, Zn and Ge. for Ge ions in Ge and for Zn ions in Zn.     

Two-quasiparticle excitations and collectivity in the weakly-deformed transitional isotopes 104, 106, 108Cd

Using the generalized centroid-shift method on the Rutgers tandem, the following half-lives of ¹⁰⁶Cd excited states were measured in the reaction ⁹³Nb(¹⁶O, p2n): $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3679.0}\text{keV}\text{) = 0.7}{}^{\mathrm{+0.1}}{}_{\mathrm{?0.3}}\text{ns}\text{, T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3507.8}\text{keV}\text{) = 1.2 ± 0.4}\text{ns}\text{, T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3044.2}\text{keV}\text{) = 0.4 ± 0.1}\text{ns, and}\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(2330.7}\text{keV}\text{) = 0.6 ± 0.2}\text{ns}$. With the same method applied on the Rossendorf cyclotron, the following half-lives were measured in the reactions ${}^{\mathrm{102,\; 106}}\text{Pd}\text{(α, 2}\text{n}\text{): T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(2902.0}\text{keV}\text{) = 0.8}{}^{\mathrm{+0.2}}{}_{\mathrm{?0.1}}\text{ns}\text{(}{}^{104}\text{Cd}\text{)}$ as well as $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3737.3}\text{keV}\text{) = 0.2 ± 0.1}\text{ns}$, $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3223.7}\text{keV}\text{) = 0.2 ± 0.1}\text{ns}$, $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3057.4}\text{keV}\text{) = 0.10 ± 0.05}\text{ns}$, $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(2975.3}\text{keV}\text{) = 0.15 ± 0.10}\text{ns}$, $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(3110.5}\text{keV}\text{) = 0.3 ± 0.1}\text{ns}$, and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(2565.2}\text{keV}\text{) = 0.2 ± 0.1}\text{ns}\text{(}{}^{108}\text{Cd}\text{)}$. The results reveal the non-collective (two-quasiparticle) character of several states above 2.9 MeV in ^{104, 106, 108}Cd, in qualitative accordance with predictions of the slightly-deformed-rotor model. They concern completely aligned [h_{$\text{11}\text{2}$}g_{$\text{7}\text{2}$}] (9^??11^?-13^?, etc.) as well as semi-decoupled [h_{$\text{11}\text{2}$}d_{$\text{5}\text{2}$}] (6^?-8^?-10^?, etc.) two-quasineutron band structures. Further, the possible character of 8⁺ (two-quasiproton) excitations, 5⁺ (two-quasineutron) states and of other intrinsic excitations is discussed. The experimental findings present a challenge to current theories of transitional nuclei for a quantitative treatment of absolute γ-ray transition strengths.     

Nuclear reaction studies of 168Tm

The intrinsic structure of ¹⁶⁸Tm has been studied using the (³He, d) and (α, t) proton stripping reactions as well as the (d, t) and (³He, α) neutron pick-up reactions. The beams of 24 MeV ³He particles, 25 MeV α-particles and 12 MeV deuterons were obtained from the McMaster tandem Van de Graaff accelerator. The reaction products were analyzed with an Enge-type magnetic spectrograph and detected with photographic emulsions. The spectra have been interpreted in terms of the coupling of an odd proton and an odd neutron, each moving independently in a spheroidal potential, which gives rise to intrinsic two-quasiparticle states with $\text{K = ¦Ω}{}_1\text{±Ω}{}_2\text{¦}$. The identification of the intrinsic states was made by comparing the experimental cross-section patterns with those predicted with the aid of Coriolis coupling and distorted-wave Born approximation (DWBA) calculations. Rotational bands superimposed on the K^π = 3⁺ and $\text{K}{}^{\mathrm{\pi }}\text{= 4}{}^{\mathrm{+}}\text{, {}\text{7}\text{2}{}^{\mathrm{+}}\text{[633]}{}_{\mathrm{n}}\text{±}\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{p}}\text{}}$ configurations, the first of which is the ground state, ha been observed in the spectra of all four reactions. New assignments have been made for configurations resulting from coupling the $\text{1}\text{2}$^? [541], $\text{7}\text{2}$⁺ [404], $\text{5}\text{4}$⁺ [402] and $\text{1}\text{2}$^? [530] p to the $\text{7}\text{2}$⁺ [633] neutron state. The neutron pick-up measurements confirmed the earlier assignments based on (d, t) reaction studies and suggested tentative assignments for the {$\text{1}\text{2}$⁺ [400]_n±$\text{1}\text{2}$⁺ [411]_p} and {$\text{3}\text{2}$⁺ [402]_n±$\text{1}\text{2}$⁺ [411]_p}     

Core polarization effects in the πh92 shell and g-factors of the 8+ states in 204Po and 206Po

The $\text{g-}\text{values of}\text{[(π}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^2\text{, 8}{}^{\mathrm{+}}\text{]}$ isomeric levels in ²⁰⁴Po and ²⁰⁶Po have been measured with the stroboscopic method. The results obtained are: $\text{g(}{}^{204}\text{Po}\text{) = 0.923±0.013}\text{and}\text{g(}{}^{206}\text{Po}\text{) = 0.919±0.013}$. These and other known $\text{g-}\text{factors of}\text{(π}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{n}}$ states in the ²⁰⁸Pb region are compared with theoretical predictions in order to analyze the dependence of the $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ proton g-value on the core constitution. The variation of the g-values is systematically smaller than expected from first-order configuration mixing theory, if pure shell-model wave functions are assumed.     

Lifetimes and g-factors of the 6− and 7− isomers in 66Ga and 68Ga

The 6^? and 7^? isomeric states in ⁶⁶Ga and ⁶⁸Ga at 1440.9 and 1229.6 keV, respectively, have been populated with the (¹³C, 2np) and (¹⁵N, n2p) reactions on natural Fe. The half-lives of these states have been measured to be $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(6}{}^{\mathrm{?}}\text{,}{}^{66}\text{Ga}\text{) = 57.3 ± 1.2}\text{ns}$ and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(7}{}^{\mathrm{?}}\text{,}{}^{68}\text{Ga}\text{) = 64 ± 2}\text{ns}$. Using previous data on the hyperfine field of Ga in Fe, the g-factors of these states have been determined by means of the TDPAD method. The results are $\text{g(6}{}^{\mathrm{?}}\text{,}{}^{66}\text{Ga}\text{) = 0.129 ± 0.003}$ and $\text{g(7}{}^{\mathrm{?}}\text{,}{}^{68}\text{Ga}\text{) = 0.105 ± 0.003}$. These values are in very good agreement with the independent particle model if one assumes the and configurations and uses the empirical proton and neutron g-factors from odd-A neighboring nuclei instead of the Schmidt values. The large disagreements with experiment when Schmidt values are used show that core polarization effects are important in these nuclei.     

Gyromagnetic ratios of excited states in 123, 125Te

The results of integral precession measurements are reported for $\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{5}\text{2}{}^{\mathrm{+}}$ excited states in ^123,125Te. The measurements were made using the ion implantation perturbed angular correlation technique by recoiling the excited nuclei into polarized iron. The measured mean lifetimes and g-factors are: ${}^{123}\text{Te (440 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) τ = 39±4 ps, g = 0.34 ± 0.06}$; $\text{(505 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) τ = 26±3 ps, g = 0.04±0.025}$; and ${}^{125}\text{Te(443 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) ρ = 27±3.3 ps, g = 0.39±0.06}$; $\text{(464 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) g = 0.12±0.04}$. The results are compared with theoretical predictions.     

Nuclear structure of 18F: (V). A further study and summary of low-lying (2s, 1d)2 states

The 6164, 6284, 6310, 6383, 6480, 6777 and 6803 keV states have been studied via the capture reactions ¹⁴N(α, γ)¹⁸F and ¹⁷O(p, γ)¹⁸F. These studies yield respective assignments of J^πT = 3⁺(1), 2⁺(0+1), 3⁺(0), 2⁺(0+1), 3⁺(0), 4⁺(0) and 1⁺, 2 or 3⁺(0). Information on radiative widths, branching and multipole mixing ratios is reported. The 6164 and 6777 keV states are well described theoretically by simple $\text{(}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}_3{}^{\mathrm{+}}\text{and}\text{(}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}_4{}^{\mathrm{+}}$ configurations, respectively. The 2⁺ states at 6284 and 6383 keV are mixed in isospin. A comparison of the observed properties with the available model calculations is presented for the above states as well as for some low-lying positive-parity states.     

Interference effects in 12C(p, γ)13N and direct capture to unbound states

Excitation functions of the capture reaction ¹²C(p, γ₀)¹³N have been obtained at θ_γ = 0° and 90° and E_p = 150–2500 keV. The results can be explained if a direct radiative capture process, E1(s and d → p), to the ground state in ¹³N is included in the analysis in addition to the two well-known resonances in this beam energy range $\text{[E}{}_{\mathrm{p}}\text{= 457(}\text{1}\text{2}{}^{\mathrm{+}}\text{)}$ and 1699 $\text{(}\text{3}\text{2}{}^{\mathrm{?}}\text{) keV]}$. The direct capture component is enhanced through interference effects with the two resonance amplitudes. From the observed direct capture cross section, a spectroscopic factor of C²S(l = 1) = 0.49 ± 0.15 has been deduced for the $\text{1}\text{2}{}^{\mathrm{?}}$ ground state in ¹³N. Excitation functions for the reaction ${}^{12}\text{C(p,γ}{}_1\text{p}{}^1\text{)}{}^{12}\text{C}$ have been obtained at θ_γ = 0° and 90° and E_p = 610–2700 keV. Away from the 1699 keV resonance the capture γ-ray yield is dominated by the direct capture process E1 (p → s) to the $\text{2366 (}\text{1}\text{2}{}^{\mathrm{+}}\text{) keV}$ unbound state. Above E_p = 1 MeV, the observed excitation functions are well reproduced by the direct capture theory to unbound states (bremsstrahlung theory). Below E_p = 1 MeV, i.e., E_p → 457 keV, the theory diverges in contrast to observation. This discrepancy is well known in bremsstrahlung theory as the “infrared problem”. From the observed direct capture cross sections at $\text{E}{}_{\mathrm{p}}\text{? 1 MeV}$, a spectroscopic factor of C²S(l = 0) = 1.02 ± 0.15 has been found for the $\text{2366 (}\text{1}\text{2}{}^{\mathrm{+}}\text{) keV}$ unbound state. A search for direct capture transitions to the $\text{3512 (}\text{3}\text{2}{}^{\mathrm{?}}\text{)}$and $\text{3547 (}\text{5}\text{2}{}^{\mathrm{+}}\text{) keV}$ unbound states resulted in upper limits of C²S(l = 1) ≦ 0.5 and C²S(l = 2) ? 1.0, respectively. The results are compared with available stripping data as well as shell-model calculations. The astrophysical aspect of the ¹²C(p, γ₀)¹³N reaction also is discussed.     

High spin states in 93mo populated in the (p,n) reaction

High spin states in the $\text{ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{(π}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^2$) multiplet in ⁹³Mo were investigated with the ⁹³Nb(p, n) ⁹³Mo reaction. A new isomeric state at 2430 keV with a half-life of 3.53±0.18 ns is interpreted as the lower $\text{17}\text{2}{}^{\mathrm{+}}$ member of the multiplet. A number of further states have been identified. The results are compared to previous experiments and shell model calculations.     

The decay process 11ΛB → π− + 11C

The branching ratios are calculated for ¹¹_ΛB decay to the ¹¹C ground and excited states below 8 MeV for two possible spin values of ¹¹_ΛB. It is found that the decay rate to the ¹¹C^★ state at E^★ = 6.48 MeV is comparable in magnitude to that leading to the ¹¹C ground state if $\text{J(}{}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{) =}\text{5}\text{2}$ is assumed. This result, unlike the branching ratios calculated for the $\text{J(}{}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{) =}\text{7}\text{2}$ case, is in accord with experiment and lends support to the assumption that $\text{J =}\text{5}\text{2}$ holds for ¹¹_ΛB. The necessity of the reinterpretation of some of the so-called ¹³_ΛC events in terms of ${}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{→ π}{}^{\mathrm{?}}\text{+}{}^{11}\text{C}{}^1$ is indicated.     

Study of the three-proton three-neutron-hole nucleus 208At

Levels in ²⁰⁸At were populated in the ²⁰⁹Bi(α, 5n) reaction, and the subsequent radiation was studied using γ-spectroscopic methods including γ-ray excitation function and angular distribution, γγ(t) coincidence and γt measurements, as well as measurements of conversion electrons. The excited spectrum of ²⁰⁸At is found to consist of two almost disconnected parts which are proposed to originate from seniority-three proton and neutron cascades. Two isometric states are observed. A $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 45 ± 2}\text{ns}$ state at 1090 keV is proposed to have the main configuration and J^π = 10^?. A high-spin isomer with $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 1.5 ± 0.2 μs at 2276}\text{keV}$ is assigned to be the state. Shell-model arguments are used to assign configurations to most of the observed levels. Transition rates are discussed.     

Hydrogen burning of 20Ne and 22Ne in stars

The ²⁰Ne(p, γ)²¹Na capture reaction has been studied in the energy range E_p = 0.37–2.10 MeV. Direct-capture transitions to the $\text{332 (}\text{5}\text{2}{}^{\mathrm{+}}\text{)}\text{and}\text{2425}\text{keV}\text{(}\text{1}\text{2}{}^{\mathrm{+}}\text{)}$ states have been found with spectroscopic factors of C²S(1d) = 0.77±0.13 and C²S(2s) = 0.90±0.12, respectively. The high-energy tail of the 2425 keV state, bound by 7 keV against proton decay, has also been observed in the above energy range as a subthreshold resonance. The excitation function for this tail is consistent with a single-level Breit-Wigner shape for a γ-width of Γ_γ = 0.31±0.07 eV at E_x = 2425 keV. The extrapolation of these data to stellar energies gives an astrophysical S-factor of S(0) = 3500 keV · b. Two new resonances at E_p = 384±5 and 417± 5 keV have been observed with strengths of ωγ = 0.11±0.02 and 0.06±0.01 meV, corresponding to the known states at and 2829 keV (presumably $\text{9}\text{2}{}^{\mathrm{+}}$), respectively. For the known E_p = 1830 keV resonance, a strength of ωγ = 1.0± 0.3 eV and a total width of Γ = 180± 15 keV were found. Branching ratios as well as transition strengths have been obtained for these three states. The Q-value for the ²⁰Ne(p, γ)²¹Na reaction (Q = 2432.3 ± 0.5 keV) as well as excitation energies for many low-lying states in ²¹Na have been measured. No evidence was found for the existence of the state reported at E_x = 4308±4 keV.In the case of ²²Ne(p, γ)²³Na, direct-capture transitions to six final bound states have been observed revealing sizeable spectroscopic factors for these states. The astrophysical S-factor extrapolated from these data to stellar energies, is S(0) = 67 ± 12 keV · b.The astrophysical as well as the nuclear structure aspects of the present results are discussed.     

Coulomb excitation of the even-mass selenium nuclei

The properties of the low-lying states of the doubly even selenium nuclei have been investigated via multiple Coulomb excitation effected with 39.2 MeV oxygen projectiles. The excitation probabilities of the first 2⁺ states of ⁷⁶Se, ⁷⁸Se and ⁸⁰Se have been determined directly by resolving inelastically and elastically scattered ⁴He projectiles on thin targets. These measurements yielded values of B(E2; 0⁺ → 2⁺) equal to $\text{0.421 ± 0.009 (}{}^{76}\text{Se}\text{), 0.321 ± 0.009 (}{}^{78}\text{Se}\text{)}\text{and}\text{0.248 ± 0.005 (}{}^{80}\text{Se}\text{) e}{}^2\text{· b}{}^2$. The multiple Coulomb excitation experiments enabled us to detect 2⁺ and 4⁺ levels in all isotopes studied up to 2.1 MeV. Moreover the double Coulomb excitation of 0⁺' states at 854.1 keV (⁷⁴Se), 1498.5 keV (⁷⁸Se), and 1478.3 keV (⁸⁰Se) was also observed. The enhancement of the E2 transition between these 0⁺' levels and the first 2⁺ states decreases rapidly with the increase of the neutron number, i.e., $\text{B(}\text{E}\text{2; 0}{}^{\mathrm{+}}\text{′ → 2}{}^{\mathrm{+}}\text{)/B(}\text{E}\text{2; 2}{}^{\mathrm{+}}\text{→ 0}{}^{\mathrm{+}}\text{) = 2.04 ± 0.08 (}{}^{74}\text{Se}\text{), 0.91 ± 0.08 (}{}^{78}\text{Se),}\text{and}\text{0.28 ± 0.04 (}{}^{80}\text{Se}\text{)}$. States interpreted as the result of direct E3 Coulomb excitation have been observed at 2350.2, 2429.2, 2507.6, and 2717.6 keV in ⁷⁴Se, ⁷⁶Se, ⁷⁸Se and ⁸⁰Se, respectively. Their B(E3; 0⁺ → 3^?) values are $\text{2.1 ± 0.5 (}{}^{74}\text{Se}\text{), 4.0 ± 0.5 (}{}^{76}\text{Se}\text{), 2.7±0.3 (}{}^{78}\text{Se}\text{)}\text{and}\text{0.9 ± 0.2 ( × 10}{}^{\mathrm{?2}}\text{e}{}^2\text{·}\text{b}{}^3$ which represent enhancements of 9.2 ± 2.2, 16.6 ± 2.1, 10.8 ± 1.2 and 3.2 ± 0.7 respectively. Furthermore, angular distribution measurements of γ-rays following Coulomb excitation with 42 MeV ¹⁶O ions in ⁷⁸Se and ⁸⁰Se have been performed. The E2 content of the 2⁺' → 2⁺ transition in these two nuclei is 87.9 % (⁷⁸Se), and 96.2 % or 33.5 % (⁸⁰Se).     

Resonance neutron capture gamma rays in 177Hf

Primary capture γ-rays have been studied for 38 ¹⁷⁷Hf neutron resonances with energies in the range 1–165 eV. Intensities were measured for 29 transitions ending at states with an excitation energy in ¹⁷⁸Hf up to 2050 keV. The analysis was facilitated by the previous knowledge of the spin and parity of all neutron resonances and of most low-lying states. For nine final levels, which had not previously been seen, information on J and π was deduced from the corresponding average intensities. The distribution of partial widths was fitted with a χ² function with ν = 1.38_?0.13^+0.18 degrees of freedom for E1 radiation and ν = 1.5_?0.40^+0.60 for M1 radiation. The average El reduced photon strength was found to be $\text{S}{}_{\mathrm{<mtext>El</mtext>}}\text{= 〈Γ}{}_{\mathrm{\gamma itij}}\text{/DE}{}_{\mathrm{\gamma }}{}^5\text{〉A}{}^{\mathrm{<mtext>?8</mtext><mtext>3</mtext>}}\text{= (4.8 ± 1.0) × 10}{}^{\mathrm{?15}}\text{MeV}{}^{\mathrm{?5}}$ and the ratio between El and Ml intensities equal to 5.5 ± 1.4. A comparison of this value for the El strength with those reported for other nuclei with A$\text{\$}\text{?}$= 100 showed that the intensities follow the A-dependence predicted by the Brink-Axel model. A non-statistical effect was observed, consisting of an enhancement of El transition probalilities to K = 2, 3 final states as compared to K = 0, 4 states.     

M1 states in 58Ni observed by proton inelastic scattering at 65 MeV

Inelastic proton scattering at 65 MeV was used to study 1⁺ states in ⁵⁸Ni. A new 1⁺ state was found at an excitation of 5.166 MeV. The angular distributions for the 1⁺ states at 2.903 and 5.166 MeV were well reproduced by a DWBA calculation under the assumptions of pure $\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}\text{and}\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$ configurations, respectively. The angular distribution for the previously suggested 1⁺ state at 7.721 MeV was not well discribed by the DWBA calculation with the isoscalar $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ wave function. The shape of the angular distribution for the 10.672 MeV, 1⁺ state was well reproduced by the DWBA calculation with the isovector $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ wave function.     

The (g92)2 residual interaction from 87Sr(d,t)86Sr

Differential cross sections for ⁸⁷Sr(d, t)⁸⁶Sr transitions to the $\text{(1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}$ states of ⁸⁶Sr were obtained with the Pittsburgh 18 MeV deuteron beam and the Enge split-pole spectrograph. States of ⁸⁶Sr up to 3.82 MeV in excitation were studied with a total resolution of 12 keV. Successful distorted-wave Born approximation (DWBA) predictions for ⁸⁷Sr(d, t) ⁸⁶Sr angular distributions permitted the extraction of l-values and spectroscopic strengths. The sum-rule value agrees with the observed value for the $\text{(1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}$ configuration. The observed $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ strength is spread over 13 states. Contrary to an earlier interpretation, the 0⁺ ground state is found to contain only 65% of the strength. Similarly, the full 4⁺ strength is not located in a single state. The new data change the interpretation of the $\text{(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}$ spectrum of ⁸⁶Sr. They significantly alter the deduced low-spin matrix elements and bring them into much closer agreement with those derived from ⁸⁸Y. Several new negative-parity states dominated by l = 1 orbital angular momentum transfer have also been identified.     

Static moments of the first excited states of 32, 34S and 204, 206Pb

The reorientation effect in Coulomb excitation has been used to measure the following static quadrupole moments: $\text{Q}{}_2\text{+ (}{}^{32}\text{S}\text{) = ?0.066 ± 0.017}\text{b}\text{, Q}{}_2\text{+ (}{}^{34}\text{S}\text{) = 0.026 ± 0.023}\text{b}\text{, Q}{}_2\text{+ (}{}^{204}\text{Pb}\text{) = 0.19 ± 0.14}\text{b}$. Interference effects from higher excited states have been included in the analysis, with the signs of the E2 matrix elements taken from an anharmonic model. The value obtained for $\text{Q}{}_2\text{+ (}{}^{32}\text{S}\text{)}$ is in disagreement with two previous measurements. We attribute the discrepancy to the smaller internucleon separation distances involved in the previous experiments, which can cause deviations from Coulomb excitation cross sections. The other quadrupole moments have not been measured previously. The B (E2: 0⁺ → 2⁺) measured were: $\text{0.0305 ± 0.0016 e}{}^2\text{·}\text{b}{}^2\text{(}{}^{32}\text{S}\text{), 0.025 ± 0.004 e}{}^2\text{·}\text{b}{}^2\text{(}{}^{34}\text{S}\text{),}\text{and}\text{0.166 ± 0.009 e}{}^2\text{·}\text{b}{}^2\text{(}{}^{204}\text{Pb}\text{)}$. From the angular distribution of the de-excitation γ-rays of the Pb nuclei following recoil into vacuum, we have determined the following $\text{g-}\text{factors}\text{: ¦g}{}_2\text{+ (}{}^{204}\text{Pb}\text{)¦ < 0.08}$ (two standard deviations), $\text{¦g}{}_2\text{+ (}{}^{206}\text{Pb}\text{)¦ = 0.07}{}^{\mathrm{+\; 0.07}}{}_{\mathrm{?\; 0.03}}$. Our value of $\text{g}{}_2\text{+ (}{}^{206}\text{Pb}\text{)}$ is in agreement with a previous measurement.     

Gamma decay of particle-core states in 209Pb

A γ-decay scheme for levels in ²⁰⁹Pb up to 4.13 MeV of excitation has been established by means of the reaction ²⁰⁸Pb(d, pγ)²⁰⁹Pb. In high efficiency p-γ coincidence measurements γ-cascades have been observed from the single-particle states and from core-excited states with very small single-particle strength. Assuming a qualitative validity of the weak-coupling model spins and main configurations of particle-core states can be deduced from their γ-decay. The $\text{J}{}^{\mathrm{\pi }}\text{= (}\text{3}\text{2}{}^{\mathrm{?}}\text{,}\text{5}\text{2}{}^{\mathrm{?}}\text{or}\text{7}\text{2}{}^{\mathrm{?}}\text{,}\text{11}\text{2}{}^{\mathrm{?}}\text{,}\text{15}\text{2}{}^{\mathrm{?}}\text{)}$ members of the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{?3}{}^{\mathrm{?}}$ multiplet could be located. A systematic manner of doublet splitting is found for the lowest states with main configuration $\text{(}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{?3}{}^{210}\text{Pb}\text{(0}{}^{\mathrm{+}}\text{, 2}{}^{\mathrm{+}}\text{, 4}{}^{\mathrm{+}}\text{, 6}{}^{\mathrm{+}}\text{, 8}{}^{\mathrm{+}}\text{)}$. A new decay branch of the $\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ single-particle state is attributed to an admixture of quadrupole core vibration.     

Low-lying states in 95Tc studied with the 93Nb(α, 2nγ)95Tc reaction

Low-lying states in ⁹⁵Tc were studied with the ⁹³Nb(α, 2nγ)⁹⁵Tc reaction. The level scheme was obtained from the γ-γ coincidence measurement. The spin assignment was made on the basis of the observed γ-ray angular distributions and the excitation functions. The $\text{337}\text{keV}\text{7}\text{2}{}^{\mathrm{+}}\text{, 627}\text{keV}\text{(}\text{5}\text{2}{}^{\mathrm{+}}\text{), 882}\text{keV}\text{13}\text{2}{}^{\mathrm{+}}\text{and}\text{957}\text{keV}\text{11}\text{2}{}^{\mathrm{+}}$ states, and possibly state, are found to be strong candidates for the core multiplet states $\text{[(1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{<mtext>p</mtext>}}\text{?2}{}^{\mathrm{+}}\text{]}{}_{\mathrm{J}}$. These states are discussed in term of a weak coupling model and the dressed three-quasiparticle model. The observed γ-ray angular distributions are compared with expectations based on a simple deexcitation model of the (α, 2nγ) reaction.