A method for calculating the ground-state properties of light closed-shell nuclei

The He⁴ nucleus ground state is studied by means of the Goldstone perturbation theory. Explicit expressions for the binding energy up to the second order in the t-interaction and for expectation values of single-particle operators (mean square radius, mass and charge distribution) up to the first order are derived. The effects of the centre-of-mass motion of the whole nucleus are considered in detail, especially with respect to mass and charge distribution. The numerical results for the charge form factor and distribution confirm the deviation from the Gaussian model measured recently.The author thanks Professor I. Úlehla for interesting discussions and M. Plchová for technical assistance.     

Macroscopic-microscopic calculations of ground state properties of superheavy nuclei

We systematically calculate the ground state properties of superheavy even-even nuclei with proton number Z=94–118. The calculations are based on the liquid drop macroscopic model and the microscopic model with the modified single-particle oscillator potential. The calculated binding energies and α-decay energies agree well with the experimental data. The reliability of the macroscopic-microscopic(MM)model for superheavy nuclei is confirmed by the good agreement between calculated results and experimental ones. Detailed comparisons between our calculations and M?ller’s are made. It is found that the calculated results also agree with M?ller’s results and that the MM model is insensitive to the microscopic single-particle potential. Calculated results are also compared with results from relativistic mean-field (RMF) model and from Skyrme-Hatree-Fock(SHF) model. In addition, half-lives, deformations and shape coexistence are also investigated. The properties of some unknown nuclei are predicted and they will be useful for future experimental researches of superheavy nuclei.     

Self-consistent calculation of the ground state properties of some rare-earth nuclei

Ground state intrinsic deformation properties of some rare earth nuclei are calculated within the Hartree-Fock approximation using a Skyrme effective interaction. After a careful optimization of basis parameters, calculations have been performed with a basis corresponding to 13 spherical oscillator shells. In order to obtain the multipole moments, good numerical convergence is necessary. Calculated quadrupole and hexadecapole moments are in agreement with available experimental data. Ground state binding energies are also well reproduced.     

Isomorphic shell model for closed-shell nuclei

The classical part of the isomorphic model for closed-shell nuclei is presented based on two physical assumptions, namely (a) the nucleons of a closed shell nucleus, considered at their most probable positions, are in an instantaneous dynamic equilibrium on spherical shells, and (b) the dimensions of the shells are determined by their close packing given that a neutron and a proton are represented by hard spheres of definite sizes. The first assumption leads to the instantaneous angular structure, and the second to the instantaneous radial structure of closed-shell nuclei. Applications of the model coming from this classical part alone and presented here are structural justification of all magic numbers, neutron (proton) and charge rms radii, nuclear densities of closed-shell nuclei, and Coulomb, kinetic, and binding energies. All the predictions are in good agreement with experimental data. A characteristic novelty of the isomphic model is that assumption (a) is related to the independent particle model, and assumption (b) to the liquid-drop model. The isomorphic model may provide a link between these two basic nuclear physics models since it incorporates features of both.     

A method for calculating adiabatic mass parameters: Application to isoscalar quadrupole modes in light nuclei

A method is given which reduces the evaluation of adiabatic inertial parameters to constrained Hartree-Fock calculations. Quadrupole masses are computed for some light nuclei. As a result of dynamical effects ¹²C is found to become oblate.     

Steepest descent in the Hilbert space - A method for calculating state vectors of ground and excited states

A new method for calculating the ground state and the excited states of a hamiltonian is proposed. We derive differential equations describing the motion of a state vector z.sfnc;Ψ(θ)〉 towards the minima of 〈Ψz.sfnc;H²z.sfnc;Ψ〉-〈Ψz.sfnc;Hz.sfnc;Ψ 〉², corresponding to the stationary states of H. As an illustration of this general scheme we determine the few lowest stationary states of an anharmonic oscillator.     

A double expansion method for calculating molecular properties

Using a form of double perturbation theory we present results of calculations on the ground state energies for the diatomic systems H₂ ⁺, HHe²⁺, H₂ and HHe⁺. For the homonuclear systems the energy values are unexpectedly good. For the heteronuclear cases the results are very encouraging and lead to optimism about the application of the method to larger systems which contain one heavy atom.     

The dynamical effects in the ground state of nuclei

Zeitschrift für Physik A Hadrons and nuclei - A method of including the dynamical effects of the multipole vibrations is proposed. The influence of the collective ground state wave function of...     

求接地导体感应电荷的一种简便方法

由一道证明题引申出一个命题,对该命题给出了证明;通过几个实例说明应用该命题可以简便地求解某些接地导体的感应电荷.     

Spin distributions in the vibrational excitations of closed-shell nuclei

Self-consistent Hartree-Fock and RPA calculations with the Skyrme-type interaction SGII are used for a systematic investigation of the 1⁺ and the triplet 0^?, 1^?, 2^? states in ⁴⁰Ca and ²⁰⁸Pb. Response functions to spin-dependent multipole operators are calculated and the particle-hole structure of the spin-dependent collective states is studied. Collective spin-dependent 0^? and 1^? states above the giant dipole resonance as well as a collective spin-independent 2^? state (twist mode) are identified. Transition spin and current densities are calculated for the collective excitations and found to be useful for the study of these excitation modes.     

计算光在引力场中偏折的新方法

利用光的量子论,能量守恒及弱等效原理得出电磁波传播在几何近似下,光线在引力场中的偏转角和波矢的关系. 利用引力场中电磁波方程,在弱场近似下给出了一般的计算光线偏转角度的方法. 具体计算了Schwarzchild引力场中光线的偏折及Kerr-Newman引力场中光线的偏折. 关键词： 引力场 电磁波方程 能量守恒 弱场近似     

Ground state properties of halo nuclei

By a rescaling both the kinetic and potential energy terms of the harmonic oscillator in conventional shell model(SM) and a mean field imitating, a self-similar-structure shell model(SSM) in which the single-particle orbits have state- or orbit-dependent frequencies was proposed to extend the SM calculations to light nuclei near the neutron drip line.     

Ground state properties of halo nuclei

By a rescaling both the kinetic and potential energy terms of the harmonic oscillator in conventional shell model(SM) and a mean field imitating, a self-similar-structure shell model(SSM) in which the single-particle orbits have state- or orbit-dependent frequencies was proposed to extend the SM calculations to light nuclei near the neutron drip line.     

Ground state properties of halo nuclei

By a rescaling both the kinetic and potential energy terms of the harmonic oscillator in conventional shell model(SM) and a mean field imitating, a self-similar-structure shell model(SSM) in which the single-particle orbits have state- or orbit-dependent frequencies was proposed to extend the SM calculations to light nuclei near the neutron drip line.     

Properties of nuclear matter andN=Z closed-shell nuclei

A simple three-parameter density dependent effective interaction is used to study the properties of nuclear matter, neutron matter and some bulk properties such as ground state energies and rms charge radii of three double-closed shell nuclei⁴He,¹⁶O and⁴⁰Ca. The three parameters of the effective interaction are determined by requiring to fit the binding energy and density of infinite nuclear matter at saturation density as well as ground state energy of¹⁶O in the first order perturbation theory. This interaction gives correct saturation in nuclear matter with a value of 283 MeV for compressibility. The symmetry coefficienta _T atk _F=1·36 fm^–1 is 28·58 MeV. The energy per particle in neutron matter is calculated in the range of nuclear matter densities and it compares well with those ofNemeth andSprung. Groundstate energies and rms charge radii of⁴He,¹⁶O and⁴⁰Ca are calculated using oscillator eigen functions as single particle wave functions. Results for ground state energies are in good agreement with empirical values and rms charge radii are slightly better than those obtained byMoszkowski with the MDI.The authors are thankful to the Computer Centre, Utkal University, Bhubaneswar for providing computational facilities for this work.     

New method for calculating the potential energy of deformed nuclei within the liquid-drop model

The method that we previously developed for going over from double volume integrals to double surface integrals in calculating the Coulomb energy of nuclei that have a sharp surface is generalized to the case of nuclei where the range of nuclear forces is finite and where the nuclear surface is diffuse. New formulas for calculating the Coulomb and the nuclear energy of deformed nuclei are obtained within this approach. For a spherically symmetric nucleus, in which case there is an analytic solution to the problem in question, the results are compared with those that are quoted in the literature, and it is shown that the respective results coincide identically. A differential formulation of the method developed previously by Krappe, Nix, and Sierk for going over from double volume integrals to double surface integrals is proposed here on the basis of the present approach.     

A simple method of observing coherent ground state transients

It is shown that coherence between nondegenerate sublevels of an atomic ground state is efficiently induced by means of a short resonant light pulse. The free precession of the coherence causes beats in forward stattering of a probe beam, which can sensitively be detected by a polarization technique. Zeeman beats on the 4f⁶ 6s²⁷ F₁-4f⁶ 6s6p ⁷F₀ transition of samarium were observed. In sodium vapor transient ground state coherence was detected in a single-shot measurement.     

Study of various ground state decay mechanisms of Actinide nuclei

The special property of the actinide mass region is that nuclei belonging to this group are radioactive and undergo different ground state processes,such as alpha decay,cluster radioactivity(CR),heavy particle radioactivity(HPR),and spontaneous fission(SF).In this study,the probable radioactive decay modes of the heavy mass region(Z=89-102) are studied within the framework of the preformed cluster model(PCM).In the PCM,the radioactive decay modes are explored in terms of the preforamation probab...     

The ground state of deformed nuclei as a boson condensate

It is shown that the ground state of deformed nuclei can be considered as a condensate of bosons that do not have a well-defined angular momentum. Values for the quadrupole moment and the particle number that are very close to the values obtained using the full boson wave function are obtained by retaining only the s- and d-parts of the boson wave function.By comparing with the many-shell (realistic) situation we found the limitations of the single-shell calculations.     

一种确定双原子分子基电子态的新方法

针对某些双原子分子基电子态与激发态势能曲线存在相交,从而引起利用从头计算确定分子基电子态时因初始输入不同而确定出的基态不同的情况,提出了一种将势能曲线计算和优化计算相结合确定基电子态的方法,并运用它确定B+2分子的基电子态.解释了文献中对于它的基电子态的计算出现不同结果的原因.