The doubly odd nucleus 144Pm: (II). Interpretation

Results from the proton transfer reactions, ¹⁴³Nd(³He, d) and ¹⁴³Nd(α, t), and γ-ray studies have been used to characterize the levels in ¹⁴⁴Pm. The spins, $\text{(}{}^3\text{He, d)}\text{(α, t)}$ cross section ratios and γ-ray branching ratios for the states below 600 keV can be interpreted consistently in terms of the mixed $\text{π2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{ν2}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and $\text{π1}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{ν2}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ shell-model configurations. The γ-ray intensity ratios measured in the ¹⁴¹Pr(α, nγ) and ¹⁴⁴Nd(p, nγ) reactions exhibit a strong and smooth dependence on level spin. Theoretical calculations employing a residual surface delta interaction are in reasonable agreement with the twelve observed low-lying negative parity states. The eight positive parity states between 841 and 1451 keV are presumed to arise from the $\text{π1}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}\text{ν2}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ configuration.     

Level structure of 48Sc from the 48Ca(p,nγ) reaction

Levels of ⁴⁸Sc up to 3.33 MeV excitation were studied by the reaction ⁴⁸Ca(p,nγ)⁴⁸Sc employing a variety of experimental techniques. A level scheme of ⁴⁸Sc comprising 29 excited states and 54 transitions were determined from the measurements of γ-γ coincidences and γ-ray excitation functions. Within the framework of the statistical compound nucleus model spins and parities of the ⁴⁸Sc levels were assigned from the angular distributions and linear polarizations of the de-excitation γ-rays as well as the excitation functions of the residual levels. From the present experimental results and other available data we tentatively identified some of the levels of the ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9$, $\text{1}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)}$, ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9\text{, 2}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$) and ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$) configurations in addition to the well-known ($\text{π}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{, v}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) multiplet.     

The (6Li, 6He) spin-isospin-flip reaction

A formulation of the (⁶Li, ⁶He) spin-isospin-flip scattering problem is presented. The method is applicable to quasielastic collisions between⁶Li described in pureLS coupling scheme and any target nucleus which can be described in a shell model or an adiabatic deformed-nucleus model picture. The effective interaction responsible for the (⁶Li, ⁶He) reaction involves an integration of the (σ₁ · σ₂) (ρ₁ · ρ₂) compo nent of the central part and the (τ₁· τ₂) tensor part of the nucleon-nucleon interaction over the internal wave function of the projectile. The ⁴⁸Ca(⁶Li,⁶He)⁴⁸Sc reaction populating the ($\text{πf}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{νf}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) multiplet in ⁴⁸Sc is analysed. It that the tensor force makes some contribution to the transitions to high spin states.     

Systematics of energies of particle-hole states in the 2s-ld and 1f72 shells

The systematics of particle-hole states in the 2s-1d and $\text{1f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ shells have been analyzed in terms of the Bansal-French-Zamick weak coupling method. States considered are $\text{d}{}^{\mathrm{?}}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{f}{}^{\mathrm{n}}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{(J =}\text{3}\text{2}{}^{\mathrm{+}}\text{), (}\text{s?d}\text{)}{}^{\mathrm{n}}\text{7}\text{2}\text{(J =}\text{7}\text{2}{}^{\mathrm{?}}\text{)}\text{and}\text{(}\text{s?d}\text{)}{}^{\mathrm{n}}\text{f}{}^2\text{7}\text{2}\text{(J = 0}{}^{\mathrm{+}}\text{and}\text{7}{}^{\mathrm{+}}\text{)}$, the jⁿ components corresponding to even-even ground states.     

Finite-range effects and nonorthogonality corrections in two-step processes of (3He,t) reactions

A full finite-range second order DWBA analysis is made for ⁴⁸Ca(³He, t)⁴⁸Sc at 23 MeV leading to the lowest 0⁺ ～ 7⁺ states of the [$\text{f}{}^{\mathrm{?}}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$] configuration taking into account both ³Heαt and ³He dt two-step processes. The effect of the finite-range of the form factors strongly reduces the contribution of ³Heαt process and the nonorthogonality corrections drastically change the contribution of ³Hedt process. Because of these effects the contributions of both processes have about the same magnitude.     

Magnetic moment of the 2543 keV 7+ state in 40K

The nuclear g-factor of the 2543 keV, 7⁺ state ⁴⁰K has been measured as g = 0.59 ± 0.10. Time-integral perturbed angular distributions were measured in an external magnetic field and, after implantation, in the hyperfine field at potassium in nickel. The experimental value is discussed within the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^2\text{and}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?2}}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^2$, configurations.     

Systematics of nn states with high spin: A study of the (α, 2He) reaction on fp shell nuclei

At 57 MeV bombarding energy the (α, ²He) reaction has been investigated on targets of ^54,56Fe, ^58,60,62,64Ni, ^64,66Zn, and ⁷⁰Ge. Selective excitation of the 2n configurations $\text{(}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{7?}}$, , and $\text{(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{6+}}$ was observed in all final nuclei. A linear A and T dependence of the binding energies of these states was observed. This systematic behaviour is well described by the Bansal-French model. The values obtained for the strength of the isoscalar and the isovector parts of the particle-hole interaction are consistent with the average of the values describing the corresponding single-particle states.     

The effective T = 1 two-particle matrix elements in the fp shell

The ⁴¹Ca($\text{d}$, p)⁴²Ca reaction has been used to locate the strength distributions for $\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ transfer in ⁴²Ca. Effective $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^2$, $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and ${}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ two-body matrix elements are derived from the data and compared to theoretical predictions.     

Radiative lifetimes in MoI using a novel atomic beam source

Radiative lifetimes of the 4d⁵ (a⁶S)5pz ⁷P^o levels and the 4d⁵ (a⁶S)5pz⁵P^o levels in MoI are reported as follows: $\text{τ(}\text{z}{}^7\text{P}{}_4{}^{\mathrm{<mtext>O</mtext>}}\text{) = 15.9}\text{ns}$, $\text{τ(}\text{z}{}^7\text{P}{}_3{}^{\mathrm{<mtext>O</mtext>}}\text{) = 17.0}\text{ns}$, $\text{τ(}\text{z}{}^7\text{P}{}_2{}^{\mathrm{<mtext>O</mtext>}}\text{) = 17.1}\text{ns}$, $\text{τ(}\text{z}{}^5\text{P}{}_3{}^{\mathrm{<mtext>O</mtext>}}\text{) = 22.3}\text{ns}$, $\text{τ(}\text{z}{}^5\text{P}{}_2{}^{\mathrm{<mtext>O</mtext>}}\text{) = 22.1}\text{ns}$, and $\text{τ(}\text{z}{}^5\text{P}{}_1{}^{\mathrm{<mtext>O</mtext>}}\text{) = 21.7}\text{ns}$ (±5%). The lifetimes are measured using time resolved laser induced fluorescence and a novel atomic beam source. This novel hollow cathode effusive beam source produces an intense beam of ground state Mo atoms and metastable Mo atoms. Our measurements on the z ⁷P^O levels are in agreement with earlier lifetime measurements. Our measurements on the z ⁵P^O levels are the first direct radiative lifetime measurements of these levels; the z ⁵P^O measurements are of particular interest because the a⁵S → z⁵P^O multiplet is used to determine the solar abundance of Mo.     

Study of the 91Zr(d, 3He)90Y reaction

The ⁹¹Zr(d, ³He) reaction was studied at a deuteron energy of 28 MeV. Angular distributions were measured from 13° to 47°; l_p values were extracted for the prominent lines of ⁹⁰Y. The l_p values and transition strengths were determined by DWBA analysis. The angular distributions for the $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ doublet (g.s. and 0.20 MeV state) exhibit the characteristic l = 1 shape. States at 1.42, 1.57, 1.64 and 1.81 MeV were also populated strongly in the (d, ³He) reaction; the 1.42, 1.57 and 1.81 MeV levels contain l= 1 transition strength and are most likely members of the $\text{(π}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the $\text{(π}\text{f}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ sextet to be unambiguously observed in this study, most probably the 5^? or 4^? member. The members of the $\text{(π}\text{g}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}$ sextet were populated weakly (less than 100 μb/sr) in this reaction.     

Coexistence of “collapse” and “blow” states of the same atom in the rare-earth region

Coexistence of two different states with the same configuration of the atom was found by means of Dirac-Fock calculations for lanthanum ($\text{6}\text{s}{}^2\text{4}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$) and europium ($\text{6}\text{s}{}^2\text{4}\text{f}{}^6{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{4}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$). The atoms in these states have different energies, self-consistent fields etc. The 4f electron in the first of these states moves in the inner well of its effective potential while in the second state it moves in the outer well.     

Kerr-effect and dielectric tensor elements of magnetite (Fe3O4) between 0.5 and 4.3 eV

The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?_xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a $\text{3d}{}^6\text{→3d}{}^5\text{(}{}^6\text{A}{}_{\mathrm{1g}}\text{) 4s}$ transition from Fe²⁺ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes $\text{3d}{}^6\text{(Fe}{}^{\mathrm{2+}}{}_{\mathrm{oct}}\text{)→3d}{}^5\text{(}{}^4\text{T}{}_{\mathrm{1g}}\text{) 4s}$ and $\text{3d}{}^5\text{(Fe}{}^{\mathrm{3+}}{}_{\mathrm{tet}}\text{)→3d}{}^4\text{(}{}^5\text{T}{}_2\text{) 4s}$, respectively, which take into account Fe 3d^n?1 final state effects.     

Mesure de la duree de vie de niveaux d'energie d'ions par transfert de coherence dans une collision de penning: Application aux niveaux 4f 2F72 et 2F52 de Mg+

Metastable 2³S₁ He atoms are optically oriented and their orientation is transferred to metallic ions produced by Penning collisions $\text{[He (2}{}^3\text{S}{}_1\text{)}\text{+ M →}\text{He (}{}^1\text{S}{}_0\text{)}\text{+ M}{}^{\mathrm{+}}\text{+}\text{e}$. If r.f. transitions are induced in the 2³S₁ He level, the circularly polarized light emitted by the ions in a direction perpendicular to the static magnetic field is modulated at the r.f. frequency. The variation of the modulation amplitude with frequency depends on the lifetime of the level of the excited ion.We describe an experimental apparatus with which we measure the modulation amplitude from 1 MHz to 110 MHz. In this way the lifetime of the 4f²F_{$\text{7}\text{2}$} and ²F_{$\text{5}\text{2}$} Mg⁺ levels has been determined.     

The (p, 2p) reaction on 6Li

The differential cross section for the quasi-elastic scattering of protons on ⁶Li is derived in the impulse approximation. The nucleus ⁵He is not treated as a bound nucleus in the derivation. Instead, the n-α interactions $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$, $\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ in the final state are included. Fits to the unknown vertex functions appearing in the expression obtained for the momentum distribution at the “ground state” of ⁵He are given, showing that the n-α $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ interaction is important at the “ground state” of ⁵He. The consistency between the observed momentum distribution and the ⁶Li form factor at low momentum transfers is shown utilizing Elton's model.     

7Li + 54Fe Single-nucleon stripping reactions at E = 48 MeV

Angular distributions have been measured for the ⁵⁴Fe(⁷Li, ⁶Li/⁶He)⁵⁵Fe, ⁵⁵Co reactions at $\text{E(}{}^7\text{Li) = 48}\text{MeV}$. Exact finite-range DWBA calculations for both reactions, employing Woods-Saxon real and imaginary potentials to generate the distorted waves, reproduce the shape of the f-state angular distributions but not the rate of fall-off with increasing angle for p-states. Using real potentials constructed by double-folding a microscopic nucleon-nucleon potential with a Woods-Saxon shaped imaginary potential to generate the distorted waves did not change the calculations. The forward angle (⁷Li, ⁶He) data allowed the $\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ states in ⁵⁵Co to be located and the determination of the single-particle centroid energies. The ⁵⁵Co spectroscopic factors are in good agreement with those from the (d, n) reaction but are generally 25 % lower than those from average (³He, d) results. The ⁵⁵Fe spectroscopic factors are in good agreement with (d, p) results.     

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.     

Effect of tensor force and one-nucleon exchange in the quasielastic (6Li, 6He) reaction

The effect of the tensor force and one-nucleon exchange is studied by applying the antisymmetrized DWBA method to the ${}^{48}\text{Ca(}{}^6\text{Li}\text{,}{}^6\text{He)}{}^{48}\text{Sc}\text{(π}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{ν}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)}{}_{\mathrm{J}}$ reaction. The exchange effect increases the cross sections but does not change the angular shapes. In contrast to the tensor force with Gaussian shape, the TWOPEP tensor contribution is larger than that of the central force and dominates the reaction for large L-transfer.