Calculation of single-particle energies in the <Stack><Subscript>38</Subscript><Superscript>96</Superscript></Stack>Sr nucleus within the mean field model with the dispersive optical potential

Evaluated and experimental neutron single-particle energies of the ^{88, 94, 96}Sr and ^{90, 96, 98}Zr nuclei near the Fermi energy are compared. A possibility of formation of a considerable particle-hole gap in the ^{94, 96}Sr typical of traditional magic nuclei is investigated. Agreement is obtained between the single-particle energies calculated within the mean field model with the dispersive optical potential and the evaluated energies for the ^{94, 96}Sr nuclei.     

Shell structure of even-even nickel isotopes containing twenty to forty neutrons

Shell parameters of even-even nickel isotopes involving twenty to forty neutrons are analyzed, and the results of this analysis are presented. A detailed comparison of the results obtained by calculating, on the basis of the mean-field model with the Koura-Yamada potential and the dispersive optical potential, single-particle energies of proton and neutron subshells with experimental data on the isotopes ^{56,58,60,62,64,68}Ni and with evaluated data on the neutron-deficient isotopes ^48,50,52,54Ni is performed.     

Quantum Monte Carlo calculation for the neutron-rich Ca isotopes

We computed ground-state energies of calcium isotopes from ⁴²Ca to ⁴⁸Ca by means of the Auxiliary Field Diffusion Monte Carlo (AFDMC) method. Calculations were performed by replacing the ⁴⁰Ca core with a mean-field self-consistent potential computed using the Skyrme interaction. The energy of the external neutrons is calculated by projecting the ground state from a wave function built with the single-particle orbitals computed in the self-consistent external potential. The shells considered were the 1F _7/2 and the 1F _5/2 . The Hamiltonian employed is semi-realistic and includes tensor, spin-orbit and three-body forces. While absolute binding energies are too deep if compared with experimental data, the differences between the energies for nearly all isotopes are in very good agreement with the experimental data.     

Optical potential analysis of proton elastic scattering from <Superscript>12</Superscript>C based on the <Emphasis Type="Italic">α</Emphasis>-particle model

Based on an α-particle model of ¹²C, an optical potential for intermediate-energy proton- ¹²C scattering is presented in the framework of the KMT theory. The parameterized proton- ⁴He amplitude, the required basic input for constructing the optical potential, is obtained by fitting the proton- ⁴He scattering data. The differential cross-sections and analyzing powers of the proton- ¹²C elastic scattering at incident energies ranging from 0.2 to 1.0GeV have been calculated by using the obtained optical potential. The main features of the measured angular distributions of the cross-section and the analyzing power can be satisfactorily described. The proton- ¹²C total cross-sections have also been calculated, and the results are in good agreement with the experimental data at energies below 0.6GeV but underestimate the data about 6% at higher energies.     

二维费密液体理论(Ⅱ)——3He朗道参数的计算

本文采用相关基波函数(CBF)方法研究了二维³He液体的性质。基于集团展开利用配分函数的变分原理,将这一方法推广到有限温度情形。从Lennard-Jones势出发,在二级微扰近似下数值计算了二维³He液体的基态能、准粒子谱和朗道参数。 关键词：     

恒星能量下核子俘获反应率的晕核效应

恒星能量下俘获截面很难直接测量。¹⁰Be（n，γ）¹¹Be俘获反应涉及到非均匀宇宙大爆炸核合成，无直接测量实验截面数据。利用转移反应¹⁰Be（d，p）¹¹Be的渐近归一化系数（ANC）方法，计算了¹⁰Be（n，γ）¹¹Be俘获反应截面和反应率。¹¹Be是中子晕核。研究表明，在恒星能量下俘获到晕态的截面和反应率显著增大。     

The 12C+24Mg elastic scattering: An example of anomalous transparency at coulomb barrier energies

Fifteen complete angular distributions of the elastic scattering of ¹²C+²⁴Mg were measured at energies around the Coulomb barrier (E_cm = 10.67–16 MeV). The angular distributions are strongly oscillating and could be well described by an optical potential family, whose real part was determined without continuous ambiguity. The imaginary part of this optical potential is very shallow. At four energies the inelastic scattering angular distributions leading to the 2⁺ state of the ²⁴Mg were also measured and analysed with coupled-channels calculations. The volume integrals of the optical potentials used in the coupled-channels calculations present the threshold anomaly in their energy dependence, with a clear Q-value dependence.     

Ab initio study of the Ar–CS2(V1B2) intermolecular potential surface: effect of van der Waals interaction on the emission of CS2 molecule

In this work, the excited state intermolecular potential energy surface of the Ar–CS₂(V¹B₂) van der Waals complex was evaluated for the first time. The calculation of more than 4000 single-point interaction energies for the complex using an equation-of-motion coupled-cluster model with single and double substitutions level of theory with extended basis set involving bond functions has been performed. After fitting the interaction energies to analytical functions, the emission spectra of the Ar–CS₂(V¹B₂) complex related to the different stationary points on the potential energy surface were calculated. It was seen that the intensity and the position of the emission spectra are dependent on the orientation of the Ar atom around the bent excited CS₂ and the distance between two components. The information about the structural parameters of the complex related to the global minimum was obtained under the pseudodiatomic approximation with assistance of ab initio potential. The presented investigation could be useful for further theoretical and experimental studies of Ar–CS₂(V¹B₂) complex.     

Large-angle 6Li + 28Si elastic and inelastic scattering at 27 and 34 MeV

Elastic and inelastic scattering data extending to θ_c.m ≈ 175° are reported for ⁶Li + ²⁸Si at 27 and 34 MeV. Optical model analyses of the elastic data were made using a variety of real potential forms. The large-angle data cannot be fitted with a Woods-Saxon real potential, but are well described by Woods-Saxon squared, double-folded or Fourier-Bessel potentials. The real potential is the same at both energies, but the imaginary potential is weaker at 27 MeV. The inelastic data were analyzed using the DWBA and coupled channels techniques with folded real form factors and deformed Woods-Saxon imaginary potentials, with the deformations taken from electron scattering. The 2⁺ state was fitted well at both energies with the DWBA, while the prediction decreased too rapidly at large angles for the 4⁺ state. The large-angle 4⁺ data were better described when two-step excitations were included in the coupled-channels calculations. The forward-angle 2⁺ data are sensitive to the interference between Coulomb and nuclear scattering and show that the nuclear and Coulomb deformation parameters β₂ are equal for this transition.     

Accurate ab initio-based DMBE potential energy surface for HLi2(X 2A′) via scaling of the external correlation

A globally accurate potential energy surface is reported for the electronic ground-state HLi₂ by fitting ab initio energies to double many-body expansion formalism. The total 3726 ab initio energies used to map the HLi₂ potential energy surface are calculated using the multi-reference configuration interaction method, with their dynamical correlation being semiempirically corrected by the double many-body expansion-scaled external correlation method. The current potential energy surface generates an excellent fit of the ab initio energies, showing a small root-mean squared derivation of 0.636 ? kcal ? mol^-1. The topographical features of the HLi₂ potential energy surface are examined in detail, which concludes that the H + Li₂(X ? ¹ Σ _g ) → Li + LiH(X ? ¹ Σ) reaction is essentially barrierless and the exothermicity is calculated to be 33.668 ? kcal ? mol^-1, thus corroborates the available experimental and theoretical results.     

Lattice energy of alkali halide crystals

A new repulsive term in the ionic interaction potential ψ(r) = Ar^?ne^?r/gl, is suggested and the three unknown parameters A, λ and n are evaluated. Lattice energies of alkali halide crystals are calculated using this form. The results agree fairly well with the experimental values.     

Radiative capture reactions with the participation of weakly bound light nuclei

Reactions of radiative capture of weakly bound light nuclei are investigated in the scope of the potential model. The applicability of the approach is demonstrated with an analysis of the cross section for the ⁶Li(p, ??)⁷Be reaction. Good agreement with the available experimental data is shown. The radiative capture cross section for the ⁶He(p, ??)⁷Li reaction in the region of low sub-barrier energies is evaluated. It is concluded that reactions involving ⁶He could also play a noteworthy part in stellar nucleosynthesis processes.     

Study of Be + C elastic scattering at energies near the Coulomb barrier

In this work, angular distribution measurements for the elastic channel were performed for the ⁹Be + ¹²C reaction at the energies ELab=13.0$E_{\mathit{Lab}}=13.0$, 14.5, 17.3, 19.0 and 21.0 MeV, near the Coulomb barrier. The data have been analyzed in the framework of the double folding São Paulo potential. The experimental elastic scattering angular distributions were well described by the optical potential at forward angles for all measured energies. However, for the three highest energies, an enhancement was observed for intermediate and backward angles. This can be explained by the elastic transfer mechanism.     

Hypernuclear binding energies in the α-particle model

The binding energies B_Λ for the hypernuclei with baryon number A = 4N + 1 up to_Λ²⁵Mg have been calculated by the variational method in the framework of Brink's α-particle model. The central ΛN potential is adjusted to the binding energy of_Λ⁵He. Due to their strong dependence on the nuclear density, the B_Λ energies are very sensitive to the choice of the effective nuclear interaction and have reasonable values for large A with the potential B1 of Brink and Boeker. The comparison with the B_Λ values obtained in the limiting shell model and the consideration of two different Λ-particle wave functions both indicate that the effect of nuclear clustering on B_Λ is significant only for_Λ⁹Be and_Λ¹³C. The nuclear distortion due to the Λ-particle binding is also evaluated in this calculation.     

Analysis of the single-particle energies of 1<Emphasis Type="Italic">f</Emphasis> and 2<Emphasis Type="Italic">p</Emphasis> proton states in <Superscript>64,66,68</Superscript>Zn nuclei by the mean field model with dispersive optical potential

Single-particle proton energies near the Fermi energy in ^64,66,68Zn are analyzed using the mean field model with dispersive optical potential. Good agreement is obtained between the calculated energies and experimental data. The set of parameters of the dispersive optical potential is compared with the set found for neighboring ^58,60,62,64Ni with the magic number Z = 28.     

Dissociation energies of SO+, SF and PBr

Experimental potential energy curves for the electronic ground states of SO⁺, SF and PBr have been constructed by using the methods of Rydberg-Klein-Rees, as modified by Vanderslice et al., as well as the authors' modification of the method of Vaidyan and Santaram. The dissociation energies of the ground states have been obtained by a curve fitting procedure using an empirical potential function with the RKRV potential energy curves. The estimated values of the dissociation energies are 5.43 ± 0.19, 3.30 ± 0.10 and 4.46 ± 0.14 eV for SO⁺, SF and PBr, respectively.     

Near-barrier fusion, breakup and scattering for the Be + Sm system

Fusion, breakup and scattering for the ⁹Be + ¹⁴⁴Sm system at near barrier energies are investigated by different approaches. We show that at energies above the barrier there is a small complete fusion suppression when compared with predictions from a double folding potential and with a similar tightly bound system. At sub-barrier energies there is no significant deviation from the predictions using coupled channel calculations that do not include the breakup channel. The energy dependence of the optical potential does not show the usual threshold anomaly found in tightly bound systems. From a simultaneous analysis of fusion and scattering data we estimate the distance where breakup starts to occur.     

Theoretical study of LiCl− and LiBr− molecular ions

The molecular structures and spectroscopic constants of the ground electronic states of LiCl^? and LiBr^? are investigated with the coupled-cluster method. To improve the accuracy of our calculations, we have employed the extrapolation schemes as well as corrections of the core–valence correlation and scalar relativistic effect. The equilibrium parameters, potential energy curves, force constants, vibrational energy levels and spectroscopic parameters of both molecular ions are derived, in which those of LiBr^? are reported for the first time. The electron affinities and vertical detachment energies of neutral and anionic LiCl and LiBr are also evaluated.