TDPADg-factor measurement of the 21/2+ state in89zr

Theg-factor of the 21/2⁺ state in⁸⁹Zr has been determined to be 0.89(4). The TDPAD method has been applied in the reaction⁸⁵Rb(⁷Li, 3n)⁸⁹Zr at 28 MeV. The obtained value agrees with shell model predictions.     

Theg-factor of the first 2+ state in192Pt by measurement of recoil into vacuum

Perturbed γ-ray angular distributions from the first 2⁺ states were measured for Coulomb-excited^{192,194,196,198}Pt recoiling into vacuum atv/c=0.010. Comparableg-factors were obtained for all four nuclei. Normalisation to the hyperfine field in¹⁹⁶Pt enabled both a comparison with a recent hydrodynamicg-factor measured in¹⁹²Pt and a cross-check of disputed Ir in Fe measurements. The followingg-factor was obtained:g(316 keV, 2⁺;¹⁹²Pt)=0.32(3).     

Ne原子(e,2e)反应中反冲离子动量分析

利用冷靶反冲离子动量谱仪,对电子轰击Ne原子的单电离反应(e,2e)进行了研究,实验测量了70—3300eV入射能量情况下,反应过程中产生的一价反冲离子的动量分布,并对反冲离子的总动量进行了还原。介绍了一个简单的碰撞机制,据此着重分析了反冲离子纵向动量和横向动量二维谱形成的原因,该碰撞机制能够较好地解释较高能量入射时的实验结果。最后根据反冲离子的动量,估算了出射电子的能量范围,为下一步进行电子、离子的符合测量奠定了基础。     

Neutral pion production at 350 MeV/u in the system20Ne +27Al

π⁰ -production probability of (9± 2)· 10^{? 3} per²⁰Ne+Al reaction has been measured at 350 MeV/u using the Two Arm Photon Spectrometer TAPS. This yield is consistent with an interpolation of published π-production rates in heavy ion collisions.     

Incomplete deep-inelastic scattering in20Ne+197Au collisions at 20 MeV/nucleon

Correlations between emission angles and energies of coincidentα-particle projectile-fragment pairs have been measured for the²⁰Ne+¹⁹⁷Au system at 390 MeV beam energy. Theα-particles observed close to the direction of the projectile-like fragment were found to result essentially from sequential projectile decay. Starting from the close-geometry data, the contribution of sequentially emittedα-particles was calculated by Monte Carlo simulations for the entire angular range. For deep inelastic events, the measured angular correlations exhibit a spectacular excess over the calculated correlation. This excess is centred close to the beam direction but on the opposite side of it with respect to the detected projectile-like fragment. The correspondingα-particles have velocities around 85% of the projectile velocity indicating emission in an early reaction phase.     

The lifetime of the 5.14 MeV state in22Ne

Using the delayed coincidence method and the reaction¹⁹F(α, pγ)²²Ne at 10.80 MeV alpha energy, the lifetime of the 5.14 MeV state in²²Ne is determined to beτ=0.84 nsec±10%.     

Stereodynamics of the reactions Ne+H2+/Ne+D2+/Ne+T2

The vector correlations between products and reagents for the reactions Ne+H + 2 , Ne+D + 2 , and Ne+T + 2 are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lü et al. [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections (2π/σ)(dσ 00 /dω t ), (2π/σ)(dσ 20 /dω t ), (2π/σ)(dσ 22+ /dω t ), and (2π/σ)(dσ 21 /dω t ), and the distributions of P (θ r ), P (φ r ), and P (θ r ,φ r ) are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed.     

Recoil effects in peripheral nucleus-nucleus collisions at E/A=84 MeV

Azimuthal angular correlations between projectile fragments and light particles have been measured in ¹⁸O induced reactions on ^58.64Ni and ¹⁹⁷Au targets at E/A=84 MeV. Neither sequential projectile decay nor evaporation from an equilibrated target-like recoil can explain the observed correlations. The data are well described in terms of a sideways-moving source suggesting emission of midrapidity light particles from a subset of nucleons which carries a major part of the transverse recoil momentum imparted by the projectile fragment.     

The magnetic moment of the first 2+ state in22Ne

Theg-factor of the 1,275 keV 2⁺ state in²²Ne has been measured by means of the time-differential recoil-into-vacuum (plunger) technique. An analysis including excited heliumlike electronic configuration was performed. A fit, which includes all these electronic states, provides a value of ¦g¦=0.36±0.03.     

First nuclear moment measurement with radioactive beams by the recoil-in-vacuum technique: the g factor of the 2+1 state in 132Te

Following Coulomb excitation of the radioactive ion beam (RIB) 132Te at HRIBF we report the first use of the recoil-in-vacuum (RIV) method to determine the g factor of the 2(+)(1) state: g(973.9 keV 2(+) 132Te) = (+)0.35(5). The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed.     

New measurements of the g factor of the 20Ne(41+) state with fs lifetime

In view of the puzzlingly small g factor, obtained for the ²⁰Ne(4₁⁺) state in previous measurements, in contradiction to all existing theoretical calculations, we have performed a new set of experiments that rigorously test the former results. Besides employing the same nuclear reaction for populating the nuclear states, new experimental features were introduced to exert strict control on the relevant parameters of the transient magnetic hyperfine field technique. The new result, g(4₁⁺)=+0.38(8), is close to theoretical predictions.     

Correlations between fission fragments and light charged-particles in the reaction20Ne+197Au at 13 MeV/nucleon

rgy of light charged-particles has been measured in coincidence with one or two fission fragments in the reaction²⁰Ne+¹⁹⁷Au at a bombarding energy of 13 MeV/u. The fission cross section was found equal to 1,340±260 mb. Assuming that it represents the totality of the fusion cross section, the critical valuel _c is deduced equal to 93±9?, higher thanl _Bf=0=74 in the rotating liquid drop model. The main emission source for protons and alpha particles seems to be a thermally equilibrated composite system. The competition between fission and charged particle emission is unexpected in the frame of the statistical treatment. A high energy component is observed in the forward direction. These results correspond to the first step of a study programme on the evolution of nucleus-nucleus collisions between 10 and 100 MeV per nucleon.     

The[g 9 2/2 ]8+ state in96Zr

An 8⁺ state has been identified at 4390 keV in the doubly semi-magic nucleus⁹⁶Zr through the study of angular correlations among the γ radiation which is emitted in the β^? decay of the 10 s isomer of⁹⁶Y. This state probably has the configuration πg ₉ ^2/2 and is populated through a GT decay from the 8⁺ member of the [πg_9/2?νg_7/2] multiplet in⁹⁶Y. The deexcitation indicates that it belongs to a band based on the 0⁺ state in⁹⁶Zr.     

Proton alignment in the 21/2+ yrast state of89Mo

The magnetic moment of the isomeric 2584 keV 21/2⁺ yrast state in⁸⁹Mo was measured via the time differential perturbed angular distribution method after recoil implantation (IMPAD) into a polarized Ni target. A g-factor of +0.79(4) was extracted, indicating a (g _9/2)² v(g _9/2)^–1 structure of this state. The result is placed in a systematic survey of g-factors in this mass region as well as compared with the prediction of shell model calculations.Communicated by: D. Schwalm     

The 21N(→d,p)22Ne reaction to the Jπ = 2+, 4.46 MeV level in 22Ne

We have used measurements of the ${}^{21}\text{Ne(}\text{→d}\text{,p)}{}^{22}\text{Ne}$ reaction to deduce spectroscopic factors for the three j_n values which contribute to the transition to the 4.46 MeV level in ²²Ne. The results agree with the shell-model calculation of Preedom and Wildenthal.     

Resonance de-enhancement in the 21 A g state oftrans-azobenzene

We analyze the origin of de-enhancement for a number of vibrational modes in the 2¹ A _g excited state oftrans-azobenzene. We have used the time-dependent wave packet analysis of the RR intensities by including the multimode damping effects in the calculation. This avoids the use of unrealistically large values for the damping parameter. It is concluded that the de-enhancement is caused by the interference between the two uncoupled electronic states, and that the intensities observed under the so-called symmetry forbidden 2¹ A _g ← 1¹ A _g transition are purely due to resonance excitation. It is also observed that the use of the time-dependent approach to study the de-enhancement effects caused by multiple electronic states on the RR intensities is not necessarily useful if one is interested in the structural dynamics.     

About the existence of anI=5/2 isobar at 1,470 MeV

The possibility that anI=5/2,Y=1,M=1,470 MeV isobar really exists is analyzed, using the experimental data reported in several papers. The existence of such an isobar in anL=1 35-plet, was already suggested by the authors.