Differential cross sections for radiative capture of energetic protons by 110Cd and 115In

Spectra of high-energy photons following the radiative capture of 8–22 MeV protons in ¹¹⁰Cd and ¹¹¹In are measured. The (p, γ) differential cross sections at 90° with respect to the beam axis is deduced from the integration of measured spectra. The photon angular distribution is measured for the ${}^{110}\text{Cd}\text{(}\text{p}\text{, γ}{}_0\text{)}$ reaction, too, at 13 MeV incident energy. Satisfactory agreement between theory and experiment is obtained by using the direct-semidirect model for dipole and quadrupole fast nucleon radiative capture.     

Observation of isomeric states and band structures in 107Cd

The odd-mass nucleus ¹⁰⁷Cd was investigated in the reactions ${}^{105}\text{Pd}\text{(α, 2}\text{n}\text{)}{}^{107}\text{Cd}\text{,}{}^{107}\text{Ag}\text{(d, 2}\text{n}\text{)}{}^{107}\text{Cd and}{}^{107}\text{Ag}\text{(}\text{p, n}\text{)}{}^{107}\text{Cd}$. The constructed level scheme is based on results, obtained from singles γ-ray spectra and excitation functions, from the measurements of delayed γ-rays, of γ-γ coincidences, of internal conversion electrons and of γ-ray angular distributions. Two new isomers were observed. The first one, interpreted as the $\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ neutron state at 845.6 keV has a half-life of 67 ± 6 ns. This isomeric state is populated by a strong E2 cascade. Bands built on the other intrinsic states with spins and parities $\text{5}\text{2}{}^{\mathrm{+}}$ and $\text{7}\text{2}{}^{\mathrm{+}}$ are not strongly populated. For the second isomeric state at an excitation energy of 2679 keV a half-life of 55±4 ns was determined. This isomer is probably a three-quasiparticle state. Its configuration can be proposed as $\text{[π(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}{}_{\mathrm{8+}}\text{ν(}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^1\text{]}{}_{\mathrm{<mtext>21</mtext><mtext>2</mtext>}}{}^{\mathrm{+}}$.     

Experimental confirmation of the anomalous IπK = 5+1 ground-state configuration of 186Ir

The quadrupole interaction frequency e²qQ/h of ¹⁸⁶Ir in hexagonal Os has been determined by nuclear orientation as +175 (10) MHz. With the known electric field gradient of ?3.00(17) × 10¹⁷ V/cm² for Ir$\text{Os}$ the spectroscopic quadrupole moment of ¹⁸⁶Ir is deduced to be ?2.41(20). This result confirm I^πK = 5⁺1 for the ground-state configuration of ¹⁸⁶Ir.     

Temperature dependence of 27Al NMR in YAlO3

The nuclear quadrupole tensor for ²⁷Al in yttrium ortho-aluminate has been measured between 30°C and ?150°C. The coupling constant $\text{e}{}^2\text{qQ}\text{h}$ varies linearly from 1.44 to 1.56 MHz over this range, whereas the asymmetry parameter η drops rapidly from 0.748 toward an asymptotic value of 0.663.     

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.     

Quadrupole moment of the 5−2, 134 keV state in 197Hg

The quadrupole interaction for the $\text{5}{}^{\mathrm{?}}\text{2}\text{, 134}\text{keV}$ state of ¹⁹⁷Hg in solid Hg was observed by the e^?-γ time differential perturbed angular correlation method. The quadrupole coupling constant ν_Q=126 (2) MHz is derived. By comparison with experimental quadrupole coupling constants for ¹⁹⁹Hg in Hg and HgCl₂ as well as for ²⁰¹Hg in HgCl₂ the quadrupole moment of the $\text{5}{}^{\mathrm{?}}\text{2}\text{, 134}\text{keV}$ state in ¹⁹⁷Hg is related to that of the ²⁰¹Hg ground state, which is known. The value $\text{Q(}{}^{197}\text{Hg}\text{,}\text{5}{}^{\mathrm{?}}\text{2}\text{, 134}\text{keV}\text{)=0.47(6)}\text{b}$ is deduced. This value is not in agreement with the assumption of a $\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ shell-model configuration for the 134 keV state. It is consistent with an interpretation of the $\text{5}{}^{\mathrm{?}}\text{2}$ level in terms of the core coupling model of de Shalit.     

The quadrupole moments of the 5− states in 116Sn, 118Sn and 120Sn

The quadrupole interaction frequencies $\text{ω}{}_0\text{=}\text{3eQ}{}_1\text{V}{}_{\mathrm{zz}}\text{41(21-1)}\text{h}\text{?}$ in the 5^? state of ¹¹⁸Sn have been measured by time differential perturbed angular correlation technique in Sn, Sb and (95% Sn+5% Sb) environments. The ω₀ for ¹¹⁶Sn was determined in Sn environment only. With the help of the known electric field gradient ¹) of Sn in a Sn lattice the quadrupole moments have been deduced as $\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{118}\text{Sn}\text{) = ±0.10(4) b}\text{and}\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{116}\text{Sn}\text{) = ±0.165(60)}\text{b}$. These values together with the known²) quadrupole moment of the analogous 5^? state in ¹²⁰Sn are interpreted in terms of the pure single-particle model. The data exhibit the expected strong systematic variation of Q_I with the number of particles in the h_{$\text{11}\text{2}$}. subshell which is being filled with 1, 3 and 5 neutrons in ¹¹⁶Sn, ¹¹⁸Sn, and ¹²⁰Sn, respectively.     

The nuclear magnetic moment of 71As and 72As

Nuclear magnetic resonance of oriented ⁷¹As and ⁷²As nuclei has been observed in an iron host lattice at low temperatures. The resonance frequencies are v_l = 174.96(10) MHz and 282.00(11) MHz respectively for zero external field. Using B_h.f.(FeAs) = 342.9(3) kG the g-factors of the two isotopes are derived as $\text{g(}{}^{71}\text{As}\text{) = (+)0.6694(7)}\text{and}\text{g(}{}^{72}\text{As) = (?)1.0789(11)}$. Combining nuclear orientation data with these results the spin of ⁷¹As has been confirmed as $\text{I =}\text{5}\text{2}$. The magnetic moments of the $\text{5}\text{2}{}^{\mathrm{?}}$ and 2^? states in the As isotopes are discussed in the framework of the shell model with configuration mixing.     

g-factors of 2.7 h 93Tc, 4.9 h 94Tc and 20 h 95Tc

The hyperfine splitting frequencies gμ_NB_H.F./h of 2.7 h ⁹³Tc $\text{(J}{}^{\mathrm{\pi }}\text{=}\text{9}\text{2}{}^{\mathrm{+}}\text{)}$, 4.9 h ⁹⁴Tc (J^π = 7⁺) and 20 h ⁹⁵Tc $\text{(J}{}^{\mathrm{\pi }}\text{=}\text{9}\text{2}{}^{\mathrm{+}}\text{)}$ as dilute impurities in Fe have been measured with NMR on oriented nuclei as 336.36(5) MHz, 175.11(1) MHz and 315.97(2) MHz, respectively. From the resonance shifts with an external magnetic field B₀ the hyperfine field of Tc$\text{Fe}$ has been determined as -317(5) kG. Taking this into account the nuclear g-factors are deduced as $\text{g(}{}^{93}\text{Tc}\text{) = 1.392(22), g(}{}^{94}\text{Tc}\text{) = 0.725(11)}\text{and}\text{g(}{}^{95}\text{Tc}\text{) = 1.308(21)}$.     

Nuclear polarization of high-spin levels and the sign of the quadrupole moment of 54Fe(10+)

The determination of the sign of the quadrupole deformation at high spins requires an observation of the electric quadrupole interaction of polarized isomers in single crystals of non-cubic metallic hosts. The ⁵⁴Fe(10⁺) isomer was polarized, subsequent to its population by the (¹²C, p2n) reaction, by passage through an array of tilted carbon foils. The isomers were then recoil implanted into single crystals of zinc and cadmium and the tune differential modulations of the angular distribution of decay γ-rays were observed. Nuclear polarization values of P_I = 0.08(3)?0.18(5) were found for 13–17 polarizing foils, respectively, and a positive sign of the quadrupole moment was deduced. An improved value was established for the quadrupole moment: $\text{Q[}{}^{54}\text{Fe}\text{(10}{}^{\mathrm{+}}\text{)] = + 29.7(4) e ·}\text{fm}{}^2$, in agreement with current shell-model predictions.     

Determination of the spectroscopic quadrupole moments of 131Cs, 132Cs and 136Cs

Nuclear spectroscopic quadrupole moments of the radioactive isotopes ¹³¹Cs, ¹³²Cs, and ¹³⁶Cs have been determined from the hyperfine structure of the $\text{6}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state by the level crossing method. The results including a Sternheimer correction are: $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{131}\text{Cs}\text{) = ?0.625(6)}\text{b}$, $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{132}\text{Cs}\text{) = +0.508(7)}\text{b}$, $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{136}\text{Cs}\text{) = +0.225(10)}\text{b}$. The quadrupole moments of all the Cs isotopes from A = 131 to A = 137 are recalculated. It is shown, that nuclear quadrupole moments of a specific isotope obtained from different atomic P-states only agree within the limits of error after application of the Sternheimer correction. The increase of Q_s with decreasing neutron number conforms with other observations and theoretical calculations stating that for elements around Z = 55 nuclear deformation develops below N = 82. The staggering of the sign of Q_s may be interpreted as consequence of an oblate-prolate degeneracy of the nuclear energy surface. Some magnetic moments have been slightly improved: $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{132}\text{Cs}\text{) = 2.219(7) μ}{}_{\mathrm{<mtext>N</mtext>}}$, $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{136}\text{Cs}\text{) = 3.705(15)μ}{}_{\mathrm{<mtext>N</mtext>}}$ (corrected for diamagnetism).     

The microwave spectrum of 14NH3 in the v = 000011 state

The frequencies and assignments of 50 lines in the pure inversion spectrum of ¹⁴NH₃ in the 0001¹ vibrational state are reported in the microwave frequency region 18–53 GHz and in selected regions up to 58 GHz.The J = 0 inversion frequency, K-type doubling constant K, l = 2, ?1 and molecular dipole moment in this state are 32 904.7 ± 2.0 MHz, 1.958 ± 0.040 MHz and 1.459 ± 0.002 D, respectively, where model inadequacies are included in the uncertainties of the first two parameters. The dipole moment measurements for this and the ground state are in excellent agreement with Stark laser measurements. An expression containing the effective l-type doubling constant is obtained from the combination of frequencies $\text{[ν(1, 1, 1) ? ν(1, 1, ?1) ? ν(2, 1, 1) + ν(2, 1, ?1)]}\text{8}\text{= 10 361.894 ± 0.004}\text{MHz}$. A preliminary value for the l-type doubling constant is 10 655 ± 20 MHz.     

Static quadrupole moment of the 8− state of 112In

The quadrupole coupling constant $\text{(}\text{eQV}{}_{\mathrm{zz}}\text{h}\text{)}$ of the 8^? 606 keV level of ¹¹²In has been measured by the DPAD method in the hexagonal lattice of metallic cadmium. The quadrupole moment of the level is deduced to be |Q| = 0.093(6) in agreement with the theoretical value for the configuration $\text{[π(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{ν(}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}{}^{\mathrm{n}}\text{]}{}_{\mathrm{8?}}$.     

Projectile Coulomb excitation of 24Mg

The static quadrupole moment of the first excited J^π = 2⁺ state in ²⁴Mg and the reduced electric quadrupole transition probability between this state and the ground state were measured via projectile Coulomb excitation. The quadrupole moment was deduced from the shapes of γ-ray angular distributions. The result is $\text{Q(}{}^{24}\text{Mg}\text{, 2}{}^{\mathrm{+}}\text{) = ?0.27±0.05}\text{b}$. The transition strength was deduced from yield measurements and by comparison with the yields of target γ-rays, The result is $\text{B(}\text{E}\text{2; 0}{}^{\mathrm{+}}\text{→ 2}{}^{\mathrm{+}}\text{,}{}^{24}\text{Mg}\text{) = 0.044±0.003 e}{}^2\text{·}\text{b}{}^2$. The experimental measurements are compared with theoretical predictions and previous measurements and a detailed discussion is given of corrections to this type of reorientation experiment.     

Sudden change of quadrupole moment between the first 52− states of 197Hg and 199Hg

Low-temperature time differential perturbed angular correlation experiments with the 164 keV-134 keV cascade of ^197mHg in a zinc matrix give evidence that the hitherto accepted value of the quadrupole moment of the first $\text{5}\text{2}{}^{\mathrm{?}}$ state of ¹⁹⁷Hg is erroneous. A new value is derived from a time differential perturbed angular correlation experiment with the 374 keV?158 keV cascade of ^199mHg implanted into a Be single crystal and comparison with an analogous experiment for ^197mHg. Taking $\text{Q(}\text{5}\text{2}{}^{\mathrm{?}}\text{,}{}^{199}\text{Hg) = +0.95(7)}\text{b}$ we derive $\text{|Q(}\text{5}\text{2}{}^{\mathrm{?}}\text{,}{}^{197}\text{Hg)¦= 0.081(6)}\text{b}$. This change of quadrupole moment is discussed in the framework of the shell model.     

Quadrupole moment of the β-emitter 17F

The quadrupole effect in the NMR of ${}^{17}\text{F}\text{(}\text{I}{}^{\mathrm{\pi }}\text{=}\text{5}\text{2}{}^{\mathrm{+}}\text{, T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 66}\text{s}\text{)}$ in a MgF₂ single crystal has been investigated. Production and implantation of polarized ¹⁷F through the ¹⁶O(d, n) reaction and the resulting asymmetric β-decay were utilized. The quadrupole coupling constant is determined to be |eqQ/h| = 8.41 ± 0.24 MHz with η = 0.32 ± 0.02 at room temperature. No appreciable temperature dependence of eqQ is found from 77 K up to 770 K. Using previously known results, the following ratios of the quadrupole moments are obtained; $\text{|Q(}{}^{17}\text{F}\text{,}\text{5}\text{2}{}^{\mathrm{+}}\text{)| : |Q(}{}^{18}\text{F}{}^1\text{, 5}{}^{\mathrm{+}}\text{)| : |Q(}{}^{19}\text{F}{}^1\text{,}\text{5}\text{2}{}^{\mathrm{+}}\text{| : |Q(}{}^{20}\text{F}\text{, 2}{}^{\mathrm{+}}\text{)|= 1 : (1.33 ± 0.08) : (1.24 ± 0.06) : (0.69 ± 0.02)}$. The additivity relation of Q between ¹⁷F, ¹⁷O, and ¹⁸F1 is discussed.     

Fine and hyperfine structure spectra of the ultra-violet 2 3S → 5 3P transition in 4He and 3He with a frequency doubled CW ring laser,detected via associative ionization

High resolution laser spectroscopy coupled to a sensitive method of detection via mass analysis of He⁺₂ ions produced in $\text{He(5}{}^3\text{P) + He(1}{}^1\text{S)}$ collisions, is used to obtain the fine and hyperfine spectra of the ultra-violet He 2 ³S → 5 ³P transition. A cw tunable UV radiation around 294.5 nm is generated by intracavity frequency doubling a Rhodamine 6G single mode ring dye laser using an ADA crystal. Both spectra enable fine and hyperfine structures to be determined within a few MHz. The magnetic dipole coupling constant A of the 5 ³P term of ³He is found to be -4326 ± 9 MHz (-0.1443 ± 0.0003 cm^-1).     

The quadrupole moment of the 535 keV state of 133La

The quadrupole moment of the 535 keV $\text{3}\text{2}{}^{\mathrm{?}}$ state of ¹³³La has been derived from a time-differential perturbed angular correlation measurement in an environment of La metal. The effective electric gradient is known from a nuclear quadrupole resonance measurement with the ground state of ¹³⁹La. The result Q = 0.35 ± 0.03 b does not confirm a proposed shape isomerism.     

Structural connections between 148Sm and 149Sm nuclei

The ^{146, 148}Nd(α, χn) and ^{148, 150}Nd(³He, χn) reactions at E_α = 20–43 MeV and E_3He = 19–27 MeV, are used to study excited states in the ¹⁴⁹Sm₈₆ and ¹⁴⁹Sm₈₇ nucleides and consequently the low-spin odd-parity excitation. The mixing ratios and multipolarities of the most prominent transitions are deduced from the combined evidence of angular distribution and electron conversion data. The spin-parity assignments for most of the levels observed are established. In ¹⁴⁸Sm the ground state band extending to I^π = 10⁺ is predominantly populated. A negative-parity odd-spin band extending from I^π = 3^?through 11^? is also observed. The bands in ¹⁴⁸Sm are interpreted within the framework of the interacting boson approximation model. In ¹⁴⁹Sm positive-parity levels with spin up to $\text{25}\text{2}$ and negative-parity levels with spins up to $\text{21}\text{2}$ are observed. The predominant γ-decay proceeds via transitions associated with $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$, $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$, $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and $\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ intrinsic configurations. The branching ratios B(E1)/B(E2) are calculated and compared in both ¹⁴⁸Sm and ¹⁴⁹Sm nucleides. The B(E1)/B(E2) dependence on the value of Z for some N = 86 (as well as 88 and 84) isotones showing a minimum of Z = 64 was noted. A 4 ns high-spin isomer mainly decaying into the positive-parity band based on the $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ state in ¹⁴⁹Sm is found. Experimental evidence is presented to interprete the $\text{1}\text{2}{}^{\mathrm{+}}$, $\text{15}\text{2}{}^{\mathrm{+}}$, … and $\text{9}\text{2}{}^{\mathrm{?}}$, $\text{13}\text{2}{}^{\mathrm{?}}$, …, ΔI = 2, sequences in ¹⁴⁹Sm as arising from the coupling of an $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ neutron to the octupole and quadrupole modes of the ¹⁴⁸Sm core nucleus. The absolute reaction cross sections for the ^{146, 148, 150}Nd(³He, χn) reactions have been determined for different bombarding energies. The mixing of the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ shells is discussed in the framework of an axial-particle-rotor model calculation.