Blocking Effect and Moments of Inertia of K = 1／2 Rotational Band in ^171Yb

The K=1/2 rotational band in ¹⁷¹Yb is investigated using the particle number conserving (PNC) method for treating the cranked shell model with monopole and quadrupole pairing interactions. The experimental moments of inertia of ¹⁷¹Yb [521]1/2 (signature α =±1/2) are reproduced well by the PNC calculation, in which no free parameter is involved. The difference in the contribution to the moment of inertia between protons and neutrons is mainly due to the blocking effect of neutron normal orbitals. The ω variation of the occupation probability of each cranked orbital and the contribution to the moment of inertia from each major shell and from each cranked orbital are investigated.     

Underlying Physics of Identical Odd-and Even-Mass Bands in Normally Deformed Rare-Earth Nuclei

The microscopic mechanism of the identical odd-and even-mass number nuclear bands in normally deformed rare-earth nuclei was investigated using the particle-number conserving (PNC) method for treating nuclear pairing correlation. It was found that the odd particle of an odd-A identical band always occupied a cranked low j and high Ω Nilsson orbital (e.g. proton [404]7/2, [402]5/2). On the contrary, if the odd particle occupies an intruder high j orbital (e.g. neutron [633]7/2, proton [514]9/2), the moment of inertia of the odd-A band was much larger than that of neighboring even-even ground state band. The observed variation of moment of inertia (below bandcrossing) was reproduced quite well by the PNC calculation, in which no free parameter was involved. The strengths of monopole and Y₂₀ quadrupole interactions were determined by the experimental odd even differences in binding energy and bandhead moment of inertia.     

超变形核中四极对力形式的探讨

用粒子数守恒方法分析了对力对于超变形(SD)带的转动惯量随角动量(角频率)变化的规律.计算中如包含了单极对力和Y₂₀四极对力,晕SD带¹⁹⁴Hg(1)和¹⁹²Hg(1)的转动惯量在观测的全部角动量范围中的变化规律,都可得到极好的重现,特别是ω≥0.40MeV时,¹⁹⁴Hg(1)的J⁽²⁾下弯和¹⁹²Hg(1)J⁽²⁾的变平.而考虑Y_2±1和Y_2±2四极对力的计算结果,都与实验不符.粒子数守恒计算中极清楚地展现了J⁽²⁾随ω变化的微观机制(可分别给出各大壳、各推转Nilsson能级上的粒子填布几率和对J⁽²⁾的贡献).J⁽²⁾随ω变化是粒子壳效应(变形场中单粒子运动)、对关联、Pauli堵塞效应以及Chriolis(反配对)作用相互竞争的结果.     

Proton Orbital [541]1/2 and Backbending in 178W

The microscopic mechanism of nine experimentally observed bands in ¹⁷⁸W is investigated using the particle-number conserving method of the cranked shell model with monopole and quadrupole paring interactions. The experimental results, including the moments of inertia and angular momentum alignments of nine bands in ¹⁷⁸W, are reproduced well by the particle-number conserving calculations, in which no free parameter is involved. Calculations demonstrate that occurrence of sharp backbending comes mainly from the contribution of high-j intruder orbitals νi13/2 or πh11/2 and their interference effect with orbitals near the Fermi surface. The ω variation of the occupation probability of each cranked orbital and the contribution to moment of inertia from each cranked orbital are analyzed.     

Particle-number-conserving analysis of multiquasiparticle bands in ~(177)Lu

The experimental one-, three-, and five-quasiparticle bands in ~(177)Lu are analyzed by the particle-number conserving (PNC) method for treating the cranked shell model with pairing interaction, in which the blocking effects are taken into account exactly. The experimental moments of inertia are reproduced very well by PNC calculations with us free parameter.     

Particle-number-conserving analysis of multiquasiparticle bands in ~(177)Lu

The experimental one-, three-, and five-quasiparticle bands in 177Lu are analyzed by the particle-number conserving (PNC) method for treating the cranked shell model with pairing interaction, in which the blocking effects are taken into account exactly. The experimental moments of inertia are reproduced very well by PNC calculations with us free parameter.     

Microscopic Mechanism of the ω Variation in Moments of Inertia for the Series of Yrast SD Bands 192—198Pb(1) and 198Po(1)

The variations in moments of inertia (J⁽²⁾ and J⁽¹⁾) with rotational frequency for the series of yrast SD bands in even-even nuclei, ^192—198Pb(1) and ¹⁹⁸Po(1), are investigated by using the particle-number conserving method for treating the pairing interaction (monopole and quadrupole). The observed co variations of J⁽²⁾ and J⁽¹⁾ are reproduced quite well in the PNC calculation, particularly the microscopic mechanism (the contributions from each major shell and each cranked Nilsson orbital) is clearly displayed. It is found that the smooth rise of J⁽²⁾ with ω is attributed to the contribution from the intruder shells (neutron N=7 and proton N=6).     

Investigation of the Type of Quadrupole Pairing Force in Superdeformed Nuclei

The variations of moments of inertia of superdeformed (SD) bands ¹⁹⁴Hg(1)and ¹⁹²Hg(1) with angular momentum (rotational frequency) are investigated using the particlenumber conserving (PNC) method for treating the cranked shell model. Calculations show that if both the monopole and Y₂₀ quadrupole pairing forces are taken into account, the observed co variation of the moments of inertia of ¹⁹⁴Hg(1) and ¹⁹²Hg(1) can be reproduced very well both in the low-and high- ranges, in particular the J⁽²⁾ downturn of ¹⁹⁴Hg(1) and the flattening in J⁽²⁾ of ¹⁹²Hg(1) at>0.40MeV. On the contrast, the calculated J⁽²⁾'s with the Y_2±1 or Y_2±2 quadrupole pairing forces are in disagreement with the experiments. The microscopic mechanism of the co variation of J⁽²⁾ is clearly exhibited in the PNC calculation (the contributions to J⁽²⁾ from various major Shells and individual cranked Nilsson orbitals, the occupancy of each cranked Nilsson Orbital etc). The variation of moment of inertia is the result of the competition among the shell effect (single particle motion in a deformed potential), pairing correlation, Pauli blocking effect and Coriolis (anti-pairing) interaction.     

Nonadditivity in moments of inertia of high-K multiquasiparticle bands

The experimental high-K 2- and 3-quasiparticle bands of well deformed rare-earth nuclei are analyzed. It is found that there exists significant nonadditivity in moments of inertia (MOIs) for these bands. The microscopic mechanism of the rotational bands is investigated by the particle number conserving (PNC) method in the frame of cranked shell model with pairing, in which the blocking effects are taken care of exactly. The experimental rotational frequency dependence of these bands is well reproduced in PNC calculations. The nonadditivity in MOIs originates from the destructive interference between Pauli blocking effects.     

Energy Staggering in Ground Bands of 232Th and 236,238U Nuclei Using the Interacting Vector Boson Model

The ΔI=2 and ΔI=4 staggering parameters of transition energies E_γ for normally deformed positive parity ground bands in ²³²Th and ^236,238U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dⁿE_γ/d Iⁿ of the γ -ray transition energies in a ΔI=2 and ΔI=4 bands, which yielding multipoint formulae. The first order derivative (two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative (five-point formula) is about 0.5 KeV and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes ^236,238U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.     

Nonadditivity in moments of inertia of high-K multiquasiparticle bands

The experimental high-K 2-and 3-quasiparticle bands of well deformed rare-earth nuclei are analyzed.It is found that there exists significant nonadditivity in moments of inertia(MOIs)for these bands.The microscopic mechanism of the rotatiohal bands is investigated by the particle number conserving(PNC)method in the frame of cranked shell model with pairing.in which the blocking effects are taken care of exactly.The experimental rotational frequency dependenEe of these bands is well reproduced in PNC calculations.The nonadditivity in MOIs originates from the destructive interference between Pauli blocking effects.     

Microscopic Mechanism of the ω Variation in Moments of Inertia for the Yrast Superdeformed Bands 194Tl(1a, 1b)

The variation in moments of inertia (J(1) and J(2)) with rotational frequency for the superdeformed bandsin odd-odd nuclei, 194Tl(la,lb), is investigated by using the particle-number conserving method for treating the pairinginteraction (monopole and quadrupole). The observed variations of J(1) and J(2) with ω are reproduced quite well inthe calculation and the contributions from each major shell are clearly displayed.     

对关联在反磁转动中的作用（英文）

采用基于推转壳模型的粒子数守恒方法对105Cd 和106Cd 中的反磁转动带进行了研究,在计算当中,粒子数严格守恒,并且堵塞效应也是严格考虑的。计算结果很好地再现了实验上观测到的I-Ω 关系、转动惯量以及约化跃迁几率B（E2）。通过检验双剪角,即两个质子空穴角动量的合拢,对反磁转动中的双剪刀机制进行了分析。研究表明剪刀角的合拢非常敏感地依赖于对关联。The antimagnetic rotation bands in 105;106Cd are investigated by the cranked shell model with pairing correlations treated by a particle-number conserving method, in which the blocking effects are taken into account exactly. The experimental moments of inertia, I-Ω relation and the reduced B(E2) transition probabilities are well reproduced. The two-shears-like mechanism for the antimagnetic rotation is investigated by examining the shears angle, i.e., the closing of the two proton hole angular momenta. The sensitive dependence of the shears angle on the nuclear pairing correlations is revealed.     

Pionic degrees of freedom in atomic nuclei and quasielastic knockout of pions by high-energy electrons

The microscopic mechanism of the identical bands in odd-odd nucleus ¹⁹⁴Tl and its neighbor odd-A nuclei ^193,195Tl is investigated using the particle-number-conserving (PNC) method for treating the cranked shell model with monopole and quadrupole pairing interactions. It is found that the blocking effect of the high-j intruder orbital plays an important role in the variation of moments of inertia (J⁽¹⁾ and J⁽²⁾) with rotational frequency for the superdeformed bands and identical bands. The variation of the occupation probability of each cranked orbital and the contributions to moment of inertia from each cranked orbital are presented.     

Quadrupole interactions in pionic and muonic tantalum and rhenium

The hyperfine splitting of pionic and muonic X-rays in natural Re has been studied using the known ratio (accurate to 1.6 parts in 10⁵) of the quadrupole moments of the two naturally occurring ¹⁸⁵Re and ¹⁸⁷Re isotopes. From the hyperfine splitting of the ⁵g → 4f and 4f → 3d pionic X-rays the effective quadrupole hyperfine constants were determined to be ¹⁸⁷A₂^eff(4f) = 1.163 ± 0.010 keV and ¹⁸⁷A₂^eff(3d) = 5.39 ± 0.63 keV, giving strong interaction quadrupole shifts ₂(4f) = 46 ± 10 eV and ₂(3d) = 1.3 ± 0.6 keV. The strong interaction monopole shifts ₀ and widths Γ₀ of the 5g, 4f and 3d levels have also been measured. For the two higher orbits, standard optical-potential calculations fit the measured shifts and widths quite well. The observed deeper-lying 3d state, however, has shifts and widths that differ by a factor of 2 or more from the predictions. From the measured quadrupole hyperfine constants of the 4f level we calculate the spectroscopic quadrupole moments to be ¹⁸⁷Q^μ(gm) = 2.09 ± 0.04 b, ¹⁸⁷Q^π = 2.07 ± 0.02 b, ¹⁸⁵Q^μ = 2.21 ± 0.04 b, and ¹⁸⁵Q^π = 2.1 addition, muonic X-rays from ¹⁸¹Ta were observed; using the same methods for determining the quadrupole moment as above, a value of ¹⁸¹Q^μ = 3.28 ± 0.06 b was obtained, in good agreement with earlier published data.     

Macroscopic-microscopic calculations of fission potential surface of uranium isotopes in the three quadratic surfaces parametrization

Five-dimensional (5D) fission potential energy surfaces (PES) for uranium nuclei are investigated based on the macroscopic-microscopic Lublin-Strasbourg drop model in the three-quadratic-surface parametrization, and the heights of static fission barriers are obtained. Asymmetric and symmetric fission paths are presented on the 5D PES of ²³⁶U for different nuclear shapes. The calculated barrier heights, E_A and E_B, are quite consistent with the experimental data for all even-even nuclei of uranium isotopes, from ²³⁰U to ²⁴⁴U.     

The low-lying rotational bands of the neutron-rich nucleus <Superscript>172</Superscript>Tm

The microscopic mechanism of four experimentally observed bands in 172Tm is investigated using the particle-number conserving method of the cranked shell model with monopole and quadrupole paring interactions.The experimental results,including the moments of inertia and angular momentum alignments of four bands in 172Tm are reproduced well by the particle-number conserving calculations.The ω variation of the occupation probability of each cranked orbital and the contribution to moment of inertia from each c...     

Cranking Calculation in the sdg Interacting Boson Model

A self-consistent cranking calculation of the intrinsic states of the sdg interacting boson model is performed. The formulae of the moment of inertia are given in a general sdg IBM multipole Hamiltonian with one- and two-body terms. In the quadrupole interaction, the intrinsic states, the quadrupole and hexadecapole deformation and the moment of inertia are investigated in the large N limit. Using a simple Hamiltonian, the results of numerical calculations for ¹⁵²,¹⁵⁴Sm and ^154-160 Gd satisfactorily reproduce the experimental data.     

Ranges of 0.2-1.0 GeV/nucleon heavy ions in nuclear photoemulsion

Heavy nuclei transport in matter are studied experimentally and theoretically. Our experimental range and straggling values of 0.2 – 1.0 GeV/nucleon ²⁰Ne, ⁴⁰Ar, ⁵⁶Fe, ¹⁹⁷Au and ²³⁸U nuclei in BR-2 nuclear photoemulsion are presented and compared with model calculations carried out according to our RANGE-program and the PRAL-model (version of 1987) developed by Ziegler et al. The presented data analysis points at the necessity to take into account Z³-correction in Bete-Bloch formula when ionization losses of very heavy multicharge ions (for example ¹⁹⁷Au and ²³⁸U) are calculated. The comparison of experimental and calculated results showed that RANGE program can correctly calculate the ranges and straggling of heavy ions. The difference between experimental and theoretical data do not exceed 5% in all of the cases examined. PRAL model describes the heavy ion ranges quite adequately, but overestimates the particle range straggling.