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.     

Shell-model studies of the 90Y, 91Zr, 92Nb and 93Mo nuclei

A shell-model calculation of the N = 51, 39 ≦ Z ≦ 42 nuclei is presented. The ⁸⁸Sr nucleus is assumed to be an inert closed core. The extra-core protons are restricted to the ($\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$) configurations, and the active neutron is allowed to occupy the $\text{2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$, $\text{3}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{1}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ orbits. The proton-proton effective interaction is directly taken from the previous analysis on the energy levels for N = 50 isotones by Ball et al. The proton-neutron effective interaction is assumed to be of the form of the surface δ-interaction. The energy spectra are calculated from a least-squares fit to the experimental data, varying the T = 0 and T = 1 strengths of the surface δ-interaction. Spectroscopic factors, E2 transition rates and two-body matrix elements are also calculated and compared with the observed values and the previous theoretical results.     

The γ-decay of the 1g92 and 2p inner-hole states in 111Sn via the 112Sn(3He, αγ) reaction at 32 MeV

The γ-decay of the deeply-bound hole states in ¹¹¹Sn has been investigated at 32 MeV incident energy by means of the ¹¹²Sn(³He, αγ) reaction. The α-particles emitted near 0° were detected in a Si counter located at the image plan of the superconducting solenoidal spectrometer SOLENO. The γ-rays in coincidence with the α-particles were detected by two Ge(Li) detectors located at 90° and 142° with respect to the beam direction, respectively. Energies, spins and decay schemes have been established for the low-lying states up to 2.5 MeV excitation energy in ¹¹¹Sn. The γ-decay of the broad bump, located around 4.2 MeV and previously attributed to neutron pick-up from the inner $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{,}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ neutron. Subshells, reveals the importance of quasiparticle-phonon m the spreading mechanism of the inner-hole strengths. The $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ and 2p strength functions have been deduced from the α-decay of the enhanced structures (3 ≦ E_x≦ 8 MeV). They are compared to the ones measured in previous inclusive neutron pick-up experiments and to those calculated in the framework of the quasiparticle-phonon nuclear model.     

Remeasurement of the low-energy cross section for the 15N(p, α0)12C reaction

The cross section for the ${}^{15}\text{N(p}\text{, α}{}_0\text{)}{}^{12}\text{C}$ reaction has been measured at θ_lab = 135° over the proton energy range 93 ≦ E_p ≦ 418 keV. The results are in good agreement with the less precise but much earlier measurements of Schardt, Fowler and Lauritsen (1952). An analysis of the present data in terms of a two-level calculation including the 338 keV (1^?) and 1028 keV (1^?) resonances determines a zero-energy intercept for the astrophysical S-factor of S(0) = 78 ± 6 MeV · b.     

g-Factors of high-spin isomers in 194Hg and 196Hg

The g-factors of the 10⁺ isomeric states in ¹⁹⁴Hg and ¹⁹⁶Hg have been measured using the in beam IPAD method. The results $\text{g(}{}^{194}\text{Hg}\text{) = ?0.24(4)}$ and $\text{g(}{}^{196}\text{Hg}\text{) = ?0.18(9)}$ are in agreement with the value expected for an ($\text{i}{}_1\text{3}\text{2}$^?2) neutron satructure and clearly contradict the previous assignment as ($\text{h}{}_{\mathrm{<mtext>1</mtext><mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?2}}$) proton configurations. Cranking model calculations show that the neutron excitation energies in the rotating frame agree satisfactorily with the experimental energies and that the proton excitations are expected ≈2 MeV above the experimental yrast line     

Neutron particle-hole electric dipole states in 206, 207, 208Pb

Inelastic proton scattering on ²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb through isobaric analog resonances has been used to study neutron particle-hole excitations with large ground-state γ-branches in these Pb isotopes. Relative (p, p′) cross sections at 90° are extracted for structures selectively excited on the $\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{,}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{and d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{?}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ resonances. Interpretation of excitations is ²⁰⁶Pb and ²⁰⁷ Pb in terms of coupling to states in ²⁰⁸Pb is discussed. Branching ratios for 1^?states in ²⁰⁸Pb at 4.84, 5.29, 5.94 and 6.31 MeV and the $\text{1}\text{2}{}^{\mathrm{+}}$ state in ²⁰⁷Pb at 4.63 MeV are deduced.     

16O(p,α0)13N cross-section measurements

Total cross sections for the ${}^{16}\text{O}\text{(}\text{p}\text{, α}{}_0\text{)}{}^{13}\text{N}$ reaction have been measured by observation of the positron decay of the residual ¹³N nuclei. These cross sections, covering the c.m. energy range 5.4 ≦ E ≦ 9.9 MeV, allow determination of reaction rates of astrophysical interest at temperatures in the neighborhood of 4 × 10⁹°K.     

Competition cusps in (α, γ) reactions

Absolute cross sections are presented for the reactions ³⁷Cl(α, γ)⁴¹K for 2.90 MeV ≦ E^lab_α ≦ 5.23 MeV, ${}^{62}\text{Ni}\text{(α, γ)}{}^{66}\text{Zn}\text{for}\text{5.07}\text{MeV}\text{≦ E}{}_{\mathrm{\alpha }}{}^{\mathrm{?2}}\text{lab}\text{≦ 8.64}\text{MeV}\text{,}{}^{62}\text{Ni}\text{(α,}\text{n}\text{)}{}^{65}\text{Zn}$ for energies near the (α, n₀) threshold at $\text{E}{}_{\mathrm{\alpha }}{}^{\mathrm{<mtext>lab</mtext>}}\text{= 6.90}\text{MeV up to}\text{8.76}\text{MeV}\text{,}{}^{64}\text{Ni}\text{(α, γ)}{}^{68}\text{Zn for}\text{4.50 ≦ E}{}_{\mathrm{\alpha }}{}^{\mathrm{<mtext>lab</mtext>}}\text{≦ 7.45}\text{MeV}$, and for ⁶⁴Ni(α, n)⁶⁷N from E_α^lab = 5.30 MeV up to E_α = 7.45 MeV. Substantial competition cusps were observed in the excitation function for all three (α, γ) reactions. The data were found to be in reasonable agreement with the predictions of the current versions of global Hauser-Feshbach models used in nucleosynthesis calculations. Including width fluctuation corrections and realistic neutron strength functions generally improves the ability of the models to predict the depth of the (α, γ) competition cusps; the depths of the predicted (α,γ) cusps are insensitive to the degree of isospin mixing. Taken together with studies of competition effects in proton-induced reactions, the present data confirm the importance of width fluctuation and strength function effects, and indicate essentially complete isospin mixing between T^< and T^> states in the compound nucleus.     

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}     

An investigation of 86Sr wave functions with the (p, α) reaction at Ep = 35 MeV

Wave functions of low-lying states in ⁸⁶Sr have been calculated in a model space including $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ sub-shells but neglecting the proton-neutron residual interaction. These wave functions have been tested by the ⁸⁹Y(p, α)⁸⁶Sr reaction at E = 35 MeV by applying a DWBA analysis with microscopic form factors.     

Influence of protons on backbending

Backbending in (at least the first half of) the rare earth nuclei seems to be determined by the alignment of an $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ neutron pair. This is supported by the disappearance of backbending due to the blocking of an $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ level by an odd neutron for example in ¹⁶⁵Yb. Contrary to expectations backbending disappears also by adding an odd $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$,proton to ₇₀¹⁶⁶Yb in ₇₁¹⁶⁷Lu for this state (but is present if the odd proton is in the $\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ level). A theory is presented which explains the odd neutron and the odd proton nuclei. It turns out that the odd proton in ¹⁶⁷Lu serves only as a type of catalyst for the alignment of an $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ neutron pair. The odd proton changes the deformation and moves the Fermi surface nearer ($\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$) or farther away ($\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$) from the nearest $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ neutron level. In one case one finds backbending and in the other case no backbending in ¹⁶⁷Lu.     

The 85Rb(p,d)84Rb reaction

The spectrum seen in single neutron pickup leading to the doubly odd nucleus ⁸⁴Rb is remarkably clean, with only five levels populated by l = 4 and six by l = 1 transitions. A simple 2J+1 weighting for the l = 4 data, combined with previous information on ⁸⁴Rb, allowed the J^π = 2^?–7^? states of the ($\text{v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}\text{? π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}$) multiplet to be identified. These data are used to determine the two-hole $\text{π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{-v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?}}$ interaction matrix elements.     

On the breaking of Bjorken scaling

In the framework of coloured quael we obtain detailed predictions for the q² dependence of the structure functions of the proton and the neutron and the $\text{σ}{}_{\mathrm{<mtext>\nu </mtext>}}\text{/σ}{}_{\mathrm{\nu }}$ ratio.     

The electron capture decay of 85gsr

In order to resolve the controversy concerning the existence of an 868 keV γ-transition in the decay of 65d ^85sSr and to determine the electron capture decay energy, radiochemically separated sources, Ge(Li), Ge(Li)-NaI(Tl), and NaI(Tl)-NaI(Tl) spectrometers have been used for singles and (X-ray-γ and γ-γ coincidence measurements. A γ-ray at 868.5±0.5 keV decaying with a 65±5 d half-life was conclusively identified in ^85gSr decay. From measurements of the ratio $\text{P}{}_{\mathrm{\kappa (868.5)}}\text{P}{}_{\mathrm{\kappa (514)}}$ of K-capture probabilities by (KX-ray-γ coincidences, a value of Q_EC was determined for the EC decay feeding the 868.5 keV transition. Thus, a level in ⁸⁵Rb is established at 868.5 keV, and an upper limit of 0.45 μsec is set on its lifetime.     

Rotational bands in 195, 197Tl

High-spin states in ^{195, 197}Tl have been populated with (α, xn) reactions and studied by means of in-beam γ-ray and e^? spectroscopic methods. Complementary studies of the decay of ^{195, 197}Pb to ^{195, 197}Tl have been carried out. Several new features have been observed in these nuclei. The $\text{9}\text{2}{}^{\mathrm{?}}$ bands of ^{195, 197}T1. extended to $\text{27}\text{2}{}^{\mathrm{(?)}}$ and $\text{29}\text{2}{}^{\mathrm{(?)}}$, respectively, show a quenching of energy spacings between the $\text{23}\text{2}{}^{\mathrm{?}}$, $\text{25}\text{2}{}^{\mathrm{?}}$, $\text{27}\text{2}{}^{\mathrm{(?}}$ and $\text{29}\text{2}{}^{\mathrm{(?}}$ states. This has been interpreted as resulting from the coupling of a $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ proton to the ($\text{π}\text{h}{}^{\mathrm{?2}}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{8+,\; 10+}}$ configurations in the core nuclei ^{194, 196}Hg. Furthermore, positive-parity bands based on $\text{15}\text{2}{}^{\mathrm{+}}$ states were established up to the $\text{35}\text{2}{}^{\mathrm{(+)}}$ and $\text{29}\text{2}{}^{\mathrm{(+)}}$ states in ^{195, 197}Tl respectively. Probably these bands originate from the coupling of a h${}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ proton to a broken neutron pair. This pair consists of a rotation-aligned $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ neutron and a low-j neutron in the $\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ or $\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ shell. It is known to constitute the 5^? bands in ^{194, 196}Hg.     

The Pn values of the 235U(nth, f) produced precursors in the mass chains 90, 91, 93–95, 99, 134 and 137–139

The first results are reported on the P_n values obtained with the recoil focussing parabolatype mass separator for unslowed fission products Lohengrin installed at the Grenoble high flux reactor. The mass chains studied were 90, 91, 93, 94, 95, 99, 134, 137, 138 and 139. Both the neutron and the β activities were measured simultaneously. The technique used to measure the neutron and the β activities and the method of analyzing the experimental data are discussed in detail. The present work led to: (i) three new periods corresponding to the new isotopes of selenium (${}^{91}\text{Se}\text{, T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 0.27±0.05}\text{sec}$), strontium (⁹⁹Sr, 0.6±0.2 sec) and telurium (¹³⁸Te, 1.3±0.3 sec); (ii) accurate periods of ${}^{99}\text{Y}\text{(T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 1.45±0.22}\text{sec}\text{)}\text{and}{}^{134}\text{Sn}\text{(0.7±0.2}\text{sec}\text{)}$; (iii) four new delayed neutron precursors consisting of ⁹¹Se, ⁹⁴Kr, ⁹⁹Sr and ¹³⁸Te; (iv) six new P_n values corresponding to the precursors ${}^{91}\text{Se}\text{(P}{}_{\mathrm{<mtext>n</mtext>}}\text{= (21±10)\%),}{}^{94}\text{Kr}\text{((5.7±2.2)\%),}{}^{99}\text{Sr}\text{((3.4±2.4)\%),}{}^{99}\text{Y}\text{((1.2±0.8)\%),}{}^{134}\text{Sn}\text{((17±13)\%)}\text{and}{}^{138}\text{Te}\text{((6.3±2.1)\%)}$; (v) a precise P_n value of the precursor ¹³⁷Te ((2.5±0.5)%); (vi) a redetermination of the P_n values of the precursors ^{90, 91}Br, ⁹³Kr, ^{93, 94, 95}Rb and ^{137, 138, 139}I. The results of this work are discussed and compared with the existing data. The low level sensitivity of the present detection system is determined to be $\text{P}{}_{\mathrm{<mtext>n</mtext>}}\text{(m)Y}{}_{\mathrm{q}}\text{(m) ? 0.4 × 10}{}^{\mathrm{?6}}\text{n}\text{/}\text{f}$ (where Y_q(m) is the cumulative yield for the mass m and the ionic charge q).     

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.     

Nanosecond lifetimes of the low-spin states in the nucleus 147Nd: A particle-rotor model interpretation of the results

Nanosecond lifetimes of several states in ¹⁴⁷Nd have been studied using the reaction ¹⁴⁶Nd(d, pγ)¹⁴⁷Nd with 10 MeV deuterons. The following lifetimes were observed: the $\text{7}\text{2}{}^{\mathrm{?}}$ level at 49.9 keV, 2.5±0.5 ns; the $\text{5}\text{2}{}^{\mathrm{?}}$ level at 127.9 keV, ≦ 0.8 ns; the $\text{9}\text{2}{}^{\mathrm{?}}$ level at 190.3 keV, 1.1±0.3 ns and the $\text{1}\text{2}{}^{\mathrm{?}}$ level at 214.6 keV, 5.8±0.8 ns. The wave functions of the states were constructed using an axial particle-plus-rotor model. The free parameters used are compared to the systematics observed in the neighbouring heavier N = 87 isotones as well as in the N = 89 and 91 isotones. Transition rates within the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and $\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ based excitations, separately, are reasonably well reproduced, but the connecting transitions indicate too strong a mixing of the shells in the calculation.     

Experimental and shell-model studies of the reactions 91Zr(d,p)92Zr and 90Zr(t,p)92Zr

The results of high-resolution studies of the ⁹¹Zr(d, p) reaction at E_d = 12 MeV and the ⁹⁰Zr(t, p) reaction at E_t = 11.85 MeV are presented. Absolute cross sections have been measured for both reactions and (d, p) spectroscopic factors determined. A comparison of these results with earlier data has been made, and although many of the previous assignments have been confirmed, many new features concerning the structure of ⁹²Zr have been discovered. Shell-model calculations have been performed for ⁹¹Zr and ⁹²Zr using a neutron space which includes the $\text{2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$, $\text{3}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$, $\text{1}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and $\text{1}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ orbits and a proton space comprising the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ and $\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ orbits. Realistic proton-neutron and neutron-neutron interactions based on the Sussex matrix elements were used in the calculations. Spectroscopic factors have been calculated for the ⁹⁰Zr(d, p) and ⁹¹Zr(d, p) reactions and cross sections calculated for the ⁹⁰Zr(t, p) reaction. In general, good agreement between the theoretical and the experimental results has been obtained.     

The proton shell closure at 14C

Data for the ¹⁴C(³He, d)¹⁵N and ¹⁴C(t, ⁴He)¹³B reactions are compared to DWBA calculations to measure the spectroscopic factors for $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{and}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ proton transitions. Good fits are found for the stripping data, as well as to similar stripping data on ¹²C. These results lower the previous value for proton $\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ hole strength in ¹⁴C by a factor of two, indicating that the neutron closure of the p-shell has provided a very good proton closed shell at ¹⁴C. Stripping results to low-lying positive parity states in ¹⁵N are interpreted within a Nilsson scheme, which reproduces the experimental results, but which requires a large deformation for the s-d orbitals.