Intensity distribution in the bands of theD 1Π →X 1Σ+ system of SnO

Relative integrated intensities of the bands of theD ¹Π →X ¹Σ⁺ system of SnO have been measured by the technique of heterochromatic photographic photometry. Using the Rydberg-Klein-Rees Franck-Condon factors andr-centroids, the variation of electronic transition momentR _e with the internuclear separationr is found to beR _e (r)=const. (0.564r−1) in the range of 1.865 A≤r≤2.041A. The relative band strengths are derived. Effective vibrational temperature of the source is found to be 2559 K.     

Reaction48Ca (p,n)48Sc fromE p =1.885 to 5.1 MeV

The total (p, n) reaction cross section for⁴⁸Ca has been measured as a function of proton energy in the energy range 1.885 to 5.100 MeV with an overall resolution of ∼ 2 keV and in ∼ 5 keV energy steps. The fluctutions in fine resolution data have been analysed to determine the average coherence width 〈Γ〉. The excitation function averaged over large energy intervals has been analyzed in terms of the optical model. The isobaric analogue resonances atE _p ∼ 1.95 and 4 MeV have been shape-analyzed to extract the proton partial width and the spectroscopic factorS _n . A comparison of the gross structures observed in ∼ 55 keV averaged excitation function with the predictions of Izumo’s partial equilibrium model has also been made.     

μ+SR study of heavy-fermion magnetism in Ce(Cu1-xNix)2Ge2

We report muon spin relaxation (μ⁺SR) studies on the magnetic phase diagram of Ce(Cu_1-xNi_x)₂Ge₂ polycrystals for 0.5≤ x ≤ 0.8. A sharp magnetic transition, evidenced by the appearance of a fast Gaussian relaxation component σ, has been observed in the x = 0.5 alloy at 4.0 K in zero applied field. The average local field < B_μ> at the stopping sites of the muons, extracted from σ, exhibits a linear temperature dependence. We associate these features with an incommensurate spin density wave (SDW) ordering. Magnetic ordering, either long range or short range, and signatures of non-Fermi liquid behaviour have not been observed down to 2.0 K at x = 0.8. This revised version was published online in August 2006 with corrections to the Cover Date.     

51(p,n)51Cr reaction from E p 1.9 to 4.5 MeV

The total cross-section for the reaction⁵¹V(p, n)⁵¹Cr has been measured fromE _p 1.9 to 4.5 MeV by using two different techniques: (i) by detecting the neutron using the 4π neutron counter and (ii) by measuring the activity of the residual nucleus⁵¹Cr. The two measurements are consistent with each other and together they are in good agreement with the data of Zyskindet al. The thermonuclear reaction rates have also been extracted starting from these cross-sections.     

High spin states in 63Cu

Excited states of ⁶³Cu were populated via the ⁵²Cr+¹⁰O (65 MeV) reaction using the gamma detector array equipped with charged particle detector array for reaction channel separation. On the basis of γ-γ coincidence relations and angular distribution ratios, a level scheme was constructed up to E _n=7 MeV and J ^π=23/2⁽⁺⁾. The decay scheme deduced was interpreted in terms of shell model calculations, with a restricted basis of the f _5/2, p _3/2, p _1/2, g _9/2 orbitals outside a ⁵⁶ ₂₈Ni core.     

On the unusual properties of the 282 keV state in <Superscript>135</Superscript>Sb

Recently the first excited state in ¹³⁵Sb has been observed at the unexpectedly low excitation energy of only 282keV and interpreted as mainly d _5/2 proton coupled to the ¹³⁴Sn core. Based on theoretical considerations it was suggested that its low excitation energy is related to a relative shift of the proton d _5/2 and g _7/2 orbits induced by the neutron excess. We have measured the lifetime of the 282keV state by the advanced time-delayed βγγ(t) method. The measured half-life, T _1/2 = 6.1(4)ns, yields exceptionally low limits of B(M1;5/2₁ ⁺→7/2₁ ⁺)≤3.0×10^-4 μ ² _N and B(E2;5/2₁ ⁺→7/2₁ ⁺)≤54e ² fm ⁴. These strongly hindered M1 and slow E2 transition rates are similar to those for the transition de-populating the first excited state at 405keV in ²¹¹Bi. Results of shell model calculations with realistic interactions are presented. The M1 decay rate was found to be extremely sensistive both to the wave function and to the M1 effective operator.     

Measurement ofL-shell photoelectric cross sections in highZ elements at 60 keV

L-shell photoelectric cross sections have been measured at 60 keV for six elements in the range 74≤Z≤92. The measurements are found to agree with theoretical calculations.     

Magnetooptical properties and FMR in granular nanocomposites (Co84Nb14Ta2) x (SiO2)100? x

For nanodimensional magnetically inhomogeneous amorphous granular films of the system (Co₈₄Nb₁₄Ta₂) _x (SiO₂)_100−x , 30≤x≤60 at.% the concentration dependences of the magnetooptical Kerr effect (MOKE) spectra and FMR have been investigated. The observed changes in the MOKE and FMR spectra are associated with transformations of microstructure and topology of the nanocomposites. For the compositions within the percolation region the transversal Kerr effect increases by an order of magnitude.     

Transmission spectra of epitaxial layers of Pb1 ? xEuxTe (0 ≤ x ≤ 0.37) solid solutions in the frequency range 7–4000 cm?1

The spectra of epitaxial Pb_{1 − x} Eu _x Te (0 ≤ x ≤ 0.37) solid solution layers grown on BaF₂ and Si substrates have been investigated over a wide frequency range 7–4000 cm⁻¹ at temperatures of 5–300 K. Apart from the phonon and impurity absorption lines, the absorption in a local mode in PbEuTe layers of substrates and buffer layers has been observed in the frequency range 110–114 cm⁻¹. As the temperature decreases from 300 to 5 K, the transverse phonon mode softens from 33.0 to 19.5 cm⁻¹.     

Luminescence of CaGa<Subscript>2</Subscript>Se<Subscript>4</Subscript>:Eu crystals

We have studied photoluminescence and thermoluminescence (PL and TL) in CaGa₂Se₄:Eu crystals in the temperature range 77–400 K. We have established that broadband photoluminescence with maximum at 571 nm is due to intracenter transitions 4f⁶ 5d–4f⁷ (⁸S_7/2) of the Eu²⁺ ions. From the temperature dependence of the intensity (log I–10³/T), we determined the activation energy (E _a = 0.04 eV) for thermal quenching of photoluminescence. From the thermoluminescence spectra, we determined the trap depths: 0.31, 0.44, 0.53, 0.59 eV. The lifetime of the excited state 4f6 5d of the Eu²⁺ ions in the CaGa₂Se₄ crystal found from the luminescence decay kinetics is 3.8 μsec. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 112–116, January–February, 2009.     

High-spin states and signature inversion in odd-odd182Au

High-spin states in¹⁸²Au have been produced and studied via the¹⁵²Sm(³⁵Cl,5nγ)¹⁸²Au reaction. The level scheme consisting of the πh _9/2⊗νi _13/2 and πi _13/2⊗νi _13/2 bands has been established for the first time. The low spin signature inversion in both bands has been found. The observed signature inversion phenomena can be interpreted qualitatively using the pairing and deformation self-consistent cranked Wood-Saxon calculations.     

Four quasi-particle level at 2256 keV in182Re

In-beam nuclear spectroscopic studies of¹⁸²Re, following the reaction¹⁸¹Ta(α, 3n)¹⁸²Re have been made using gamma-ray and internal conversion electron techniques.K-conversion coefficients for several transitions have been measured and the multi-polarities of the various transitions assigned. In particular, the spin and parity of the four-quasi-particle isomeric level at 2256 keV were determined to be 16⁻. Theg-factor of this level has been measured to beg = 0·32 ± 0·05. On the basis of theg-factor and the decay pattern of this level, a configuration {v9/2⁺ [624↑]v7/2⁻ [514↓]v7/2⁻ [503↑]π9/2⁻ [514↑]} _k ^x = 16⁻ has been assigned to this level. The nature of the retardation of the gamma transitions deexciting this level is discussed. It is argued that the measured retardation factors can be explained if the nucleus has a triaxial shape.     

Measurement and analysis of alpha particle induced reactions on gold

Stacked foil activation technique and Ge(Li) gamma ray spectroscopy have been used for the measurement of excitation functions of¹⁹⁷Au(α,xn) (x=1−3),¹⁹⁷Au(α,2pn) and¹⁹⁷Au(α,αn) reactions up to 50 MeV. The experimental cross-sections were compared with the predictions of pre-equilibrium hybrid model, as well as with the more recent index model. A general agreement was found in all reactions using initial exciton numbern ₀=4(4p0h) except for¹⁹⁷Au(α,n) reaction, where index model gives fairly good agreement withn ₀=5(5p0h).     

Group theoretical aspects ofU B(6) ⊗U F(20) symmetry limits of IBFM related to theU B(5) andO B(6) limits of IBM

TheU ^B(6)⊗U ^F(20) Bose-Fermi dynamical symmetry of interacting boson-fermion model arises when the odd nucleon occupies single particle orbits withj=1/2, 3/2, 5/2, and 7/2. The subgroup structures ofU ^B(6)⊗U ^F(20) related to theU ^B(5) andO ^B(6) limits of sdIBM (U ^B(6)) are analysed. Broadly speaking,U ^B(6)⊗U ^F(20) admitsU ^BF(5)⊗U _s ^F (4), Spin^BF(5)⊗U _k ^F (5) andU ^BF(5)⊗U _s ^F (2) limits withU ^B(5) core and Spin^BF(6),O ^BF(5)⊗U _s ^F (4), Spin^BF(6)⊗U _k ^F (5) andO ^BF(6)⊗U _s ^F (2) limits withO ^B(6) core respectively. For each of these seven symmetry limits, group chains, quantum numbers labelling the basis states, generators and Casimir operators for the various subgroups and energy formulas are given. Recoupling coefficients (reduced Wigner coefficients) for constructing wavefunctions of low-lying states are tabulated and these will allow (together with sdIBMU ^B(5) andO ^B(6) limit results) one to calculateB(E2)’s,B(M1)’s, one and two nucleon transfer strengths etc. in the seven symmetry limits. Experimental examples for theU ^B(6)⊗U ^F(20) symmetry limits are briefly discussed.     

Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)

The spin polarized β-emitting nuclei¹²B (I ^π=1⁺,T _1/2=20.18 ms) were produced by the nuclear reaction¹¹B(d, p)¹²B and by the selection technique of the incident deuteron energy and the¹²B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei¹²B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment of¹²B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift.     

UV excitable Y2? x ? y Gd y SiO5:Ce x phosphors for cool white light emission

Cool white light was realized in Y_2−x−y Gd _x SiO₅: Ce _y phosphor under near UV excitation, due to the occupation Ce³⁺ in Y³⁺ 1st and 2nd site, synthesized using solid state carbothermal reduction route. SEM with elemental analysis show the existence of Gd in Y₂SiO₅:Ce enhances the particles size in comparison to Y₂SiO₅:Ce phosphors alone. Gd³⁺ (0.00≤x≤0.75) and Ce³⁺ (0.02≤y≤0.10) concentration was optimized to 0.50 and 0.08 in Y₂SiO₅, respectively. The CIE chromaticity color coordinates (0.24, 0.20) are close to cool white light value which could be useful for the fabrication of cool white LED.     

μ + SR studies of antiferromagnetic chromiumSR studies of antiferromagnetic chromium

μ ⁺ SR measurements have been performed on Cr single crystals at temperatures 60 mK≤T≤295 K in applied magnetic fields 0≤B _appl≤1.5 T. The temperature dependence of the observed precession frequencies and transverse relaxation rates can be explained by the assumption that theμ ⁺ are hopping between adjacent tetrahedral interstices. At temperaturesT≤11 K evidence for an interaction between theμ ⁺ and the spin-density waves in Cr has been found. The directions and magnitudes of the lattice magnetic moments are unaffected by the applied magnetic fields.     

Isochronous Mass Measurements of Hot Exotic Nuclei

A novel method for mass measurements of short-lived exotic nuclides is presented. Exotic nuclides were produced and separated in flight at relativistic energies with the fragment separator (FRS) and were injected into the experimental storage ring (ESR). Operating the ESR in the isochronous mode we performed mass measurements of neutron deficient fragments of ⁸⁴Kr with half-lives larger than 50 ms. However, this experimental technique is applicable in a half-life range down to a few μs. A mass resolving power of 110000 (FWHM) has been achieved. Results are presented for the masses of ⁶⁸As, ^70,71Se and ⁷³Br. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fluctuating Electric Field Gradients at 111Cd in Ice

¹¹¹Cd–PAC measurements have been made using the high specific activity of ¹¹¹In in the methanol–water mixtures of various concentrations at the room temperature. These experiments revealed that the perturbation factors 〈A ₂ G ₂〉 (integrated over two mean lives τ_N) do not follow the dependence of the macroscopic viscosity η. The observed dynamic character of the PAC spectra in ice is explained by the mobility of orientational and ionic defects. The activation energy for the diffusion process was determined to be E _a =0.35(1) eV. This revised version was published online in September 2006 with corrections to the Cover Date.     

Determination of Trace Mercury by Solid Substrate-Room Temperature Phosphorimetry Quenching Method Based on Catalytic Effect of Hg2+on Formation of the Ion Association Complex [Sn(XO)6]4+·[(Fin)4]

A new method for the determination of trace mercury by solid substrate-room temperature phosphorimetry (SS-RTP) quenching method has been established. In glycine-HCl buffer solution, xylenol orange (XO) can react with Sn⁴⁺ to form the complex [Sn(XO)₆]⁴⁺. [Sn(XO)₆]⁴⁺ can interact with Fin⁻ (fluorescein anion) to form the ion associate [Sn(XO)₆]⁴⁺·[(Fin)₄]⁻, which can emit strong and stable room temperature phosphorescence (RTP) on polyamide membrane (PAM). Hg²⁺ can catalyze H₂O₂ oxidizing the ion association complex [Sn(XO)₆]⁴⁺·[(Fin)₄]⁻, which causes the RTP to quench. The ΔIp value is directly proportional to the concentration of Hg²⁺ in the range of 0.016–1.6 fg spot⁻¹ (corresponding concentration: 0.040–4.0 pg ml⁻¹, 0.40 μl spot⁻¹), and the regression equation of working cure is ΔIp=10.03+83.15 m Hg²⁺ (fg spot⁻¹), (r=0.9987, n=6) and the detection limit (LD) is 3.6 ag spot⁻¹(corresponding concentration: 9.0×10^–15 g ml⁻¹, the sample volume: 0.4 μl). This simple, rapid, accurate method is of high selectivity and good repeatability, and it has been successfully applied to the determination of trace mercury in real samples. The reaction mechanism for catalyzing H₂O₂ oxidizing the ion association complex ([Sn(XO)₆]⁴⁺·[(Fin)₄]⁻) SS-RTP quenching method to determine trace mercury is also discussed.