Screening-Dependent Study of Superconductivity in 3d-Transition Metals Binary Alloys Superconductors

In the present article, we report the screening-dependent study of the superconducting state parameters （SSPs）, viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^＊, transition temperature TC, isotope effect exponent a, and effective interaction strength No V of 3d-band transition metals binary alloys superconductors have been made extensively in the present work using a model potential formalism and employing the pseudo-alloy-atom （PAA） model for the first time. Five local field correction functions proposed by Hartree （H）, Taylor （T）, Ichimaru-Utsumi （IU）, Farid et al. （F） and Sarkar et al. （S） are used in the present investigation to study the screening influence on the aforesaid properties. The present results of the SSPs obtained from H-screening are found in qualitative agreement with the available experimental data wherever exist.     

Energy and fine structure of 1s2np(n≤9) states for lithium-like systems from Z=11 to 20

A new variation method is extended to study the atomic systems with higher nuclear charges and in more highly excited states. The non-relativistic energies of 1s^2np (n≤9) states for the lithium-like systems from Z=11 to 20 are calculated using a full-core-plus-correlation method with multi-configuration interaction wavefunctions. Relativistic and mass-polarization effects on the energy are calculated as the first-order perturbation corrections. The fine structures are determined from the expectation values of spin-orbit and spin-other-orbit interaction operators in the Pauli－Breit approximation. The quantum-electrodynamics correction is also included. Our results are compared with experimental data in the literature.     

Relativistic calculations of 3s2 1S0-3s3p 1P1 and 3s2 1S0-3s3p 3P1,2 transition probabilities in the Mg isoelectronic sequence

Using the multi-configuration Dirac-Fock self-consistent field method and the relativistic configuration-interaction method,calculations of transition energies,oscillator strengths and rates are performed for the 3s 2 1 S 0-3s3p 1 P 1 spinallowed transition,3s 2 1 S 0-3s3p 3 P 1,2 intercombination and magnetic quadrupole transition in the Mg isoelectronic sequence(Mg I,Al II,Si III,P IV and S V).Electron correlations are treated adequately,including intravalence electron correlations.The influence of the Breit interaction on oscillator strengths and transition energies are investigated.Quantum electrodynamics corrections are added as corrections.The calculation results are found to be in good agreement with the experimental data and other theoretical calculations.     

Theoretical study on K, L, and M X-ray transition energies and rates of neptunium and its ions

The transition energies and electric dipole （El） transition rates of the K, L, and M lines in neutral Np have been theoretically determined from the MultiConfiguration Dirac-Fock （MCDF） method. In the calculations, the contributions from Breit interaction and quantum electrodynamics （QED） effects （vacuum polarization and self-energy）, as well as nu- clear finite mass and volume effects, are taken into account. The calculated transition energies and rates are found to be in good agreement with other experimental and theoretical results. The accuracy of the results is estimated and discussed. Furthermore, we calculated the transition energies of the same lines radiating from the decaying transitions of the K-, L-, and M-shell hole states of Np ions with the charge states Np1＋ to Np6＋ for the first time. We found that for a specific line, the corresponding transition energies relating to all the Np ions are almost the same; it means the outermost electrons have a very small influence on the inner-shell transition processes.     

Superconducting State Parameters of CucZr100-c Binary Amorphous Alloys by Pseudopotential Approach

We present the screening dependence theoretical investigations of the superconducting state parameters, i.e. electron-phonon coupling strength A, Coulomb pseudopotential μ＊, transition temperature To, isotope effect exponent α, and effective interaction strength NoV of some CucZr100-c （C = 25, 30, 33, 35, 40, 45, 50, 55, 57, 60 at.%） binary amorphous alloys by employing the well-known empty core model potential of Ashcroft. Five screening functions proposed by Hartree, Taylor, Ichimaru-Utsumi, Farid et al. and Sarkar et al. are used to study the screening influence on the aforesaid superconducting properties. The transition temperature Tc obtained from the Ichimaru-Utsumi screening function is found to be in excellent agreement with available theoretical or experimental data. Also, the present results are found in qualitative agreement with the other earlier reported data, which confirms the superconducting phase in the amorphous alloys.     

Calculations of 2s^2S1／2—2P^2P1／2,3／2 Transition Energies for Lithium—Like Systems from Na IX to Ca XⅧ

The transition energies (2ss S1/2-2p2P1/2,3/2) of lithium-like systems with nuclear charge from Z=11-20 are calculated by using a full-core plus correlation method.Relativistic and mass-polarization effects on the energies are included as the first-order perturbation corrections.The quantum-electrodynamics contributions to the transition energy are evaluated by using efective nuclear charge.Our results are in excellent agreement with previous theoretical and experimental data available in the literature.     

Relativistic Energies and Auger Widths of High-Lying Doubly-Excited States 1s^23lnl′ ^1De in Be-Like O^4＋ Ions

The saddle-point variational method and restricted variational method are used to calculate energies of doublyexcited singlet states 1s^23lnl′ （n =3-.） ^1 De in Be-like O^4＋ ions, including the mass polarization and relativistic corrections. The saddle-point complex-rotation method is used to compute the Auger widths and Auger transition rates. These results are compared with other theoretical and experimental data in the literature.     

Evolution of Holographic Dark Energy in Interacting Modified Chaplygin Gas Model

We investigate the modified Chaplygin gas （MCG） with interaction between holographic dark energy proposed by Li and dark matter. In this model, evolution of the universe is described in detail, which is from deceleration to acceleration. Specifically, the evolutions of related cosmological quantities such as density parameter, the equation of state of holographic dark energy, deceleration parameter and transition redshift are discussed. Moreover, we also give their present values which are consistent with the lately observations. Furthermore, the results given by us show such a model can accommodate a transition of the dark energy from a normal state wx 〉 -1 to ωx 〈 -1 phantom regimes.     

Theoretical analysis on fully differential cross sections for C~(6+)impact ionization of helium

Fully differential cross sections （FDCS） are calculated within a four-body model for single ionization of helium by C6＋ impact at the incident energy of 100 MeV/a.u. （atomic unit）. The results are compared with experimental data and other theoretical predictions. It is shown that our results are in very good agreement with experiment for three small momentum transfers in the scattering plane; however, some significant discrepancies are still present at the largest momentum transfer in both the scattering plane and the perpendicular plane. In actuality, the problem has not been explained by the theory during the last decade. Accordingly, the contributions of different scattering amplitudes to FDCS are analyzed. It is found that for the largest momentum transfer the cross section arising from a destructive interference of the three amplitudes is much smaller than the experimental data. However, the cross section due to the constructive interference of two scattering amplitudes between projectile-ionized electron interaction and projectile-passive electron interaction almost approaches the experimental data.     

Wavefunction and energy of the 1s22sns configuration in a beryllium atom

A new set of trial functions for 1s^22sns configurations in a beryllium atom is suggested. A Mathematica program based on the variational method is developed to calculate the wavefunctions and energies of 1s^22sns （n = 3 - 6） configurations in a beryllium atom. Non-relativistic energy, polarization correction and relativistic correction which include mass correction, one- and two-body Darwin corrections, spin-spin contact interaction and orbit-orbit interaction, are calculated respectively. The results are in good agreement with experimental data.     

Photoproduction of the $\Theta^+$ and its vector and axial-vector structure

We present recent investigations on the vector and axial-vector transitions of the baryon antidecuplet within the framework of the self-consistent SU（3） chiral quark-soliton model, taking into account the 1/No rotational and linear mscorrections. The main contribution to the electric-like transition form factor comes from the wave-function corrections. This is a consequence of the generalized Ademollo-Gatto theorem. It is also found that in general the leading-order contributions are almost canceled by the rotational 1/No corrections. The results are summarized as follows： the vector and tensor K＇NO coupling constants, gK＊N= 0.74--0.87 and fk＊N =0.53--1.16, respectively, and F→KN = 0.71 MeV, based on the result of the KN coupling constant gKne =0.83. We also show the differential cross sections and beam asymmetries, based on the present results. We also discuss the connection of present results with the original work by Diakonov, Petrov, and Polyakov.     

Non-Adiabatic Effects of Superconductor Silane under High Pressure

We present the investigations of non-adiabatic effects by including vertex corrections in the standard Eliashberg theory and show that high phonon frequency is unfavorable to superconductivity in the regime of strong vertex correction. This means that it is hard to find high-transition-temperature superconductors in the compounds with light elements if the non-adiabatic effects are strong. The interplay interaction between non-adiabatic effect and Coulomb interaction makes the transition temperature of silane superconductor not so high as predicted by the standard Eliashberg theory.     

Systematic Study on Alpha Decay Half-Lives of Superheavy Nuclei

The α-decay half-lives of a set of superheavy nuclear isotope chain from Z = 105 to 120 have been analyzed systematically within the WKB method, and some nuclear structure features are found. The decay barriers have been determined in the quasi-molecular shape path within the Generalized Liquid Drop Model （GLDM） including the proximity effects between nucleons in a neck and the mass and charge asymmetry. The results are in reasonable agreement with the published experimental data for the alpha decay half-llves of isotopes of charge 112, 114, and 116, of the element 294118 and of some decay products. A comparison of present calculations with the results by the DDM3Y effective interaction and by the Viola-Seaborg-Sobiczewski （VSS） formulae is also made. The experimental a decay half lives all stand in between the GLDM calculations and VSS formula results. This demonstrates the possibility of these models to provide reasonable estimates for the half-lives of nuclear decays by a emissions for the domain of SHN. The half-lives of these new nuclei are thus well tested from the reasonable consistence of the macroscopic, the microscopic, the empirical formulae and the experimental data. This also shows that the present data of SHN themselves are consistent. It could suggest that the present experimental claims on the existence of new elements Z =110 - 118 are reliable. It is expected that greater deviations of a few SHN between the data and the model may be eliminated by further improvements on the precision of the measurements.     

Superconducting State Parameters of NbxTayMoz Superconductors

We present screening dependence theoretical investigations of the superconducting state parameters, i.e. electron-phonon coupling strength λ, Coulomb pseudopotential μ＊, transition temperature TC, isotope effect exponent α, and effective interaction strength N0V, of some BMG superconductors, namely Nb0.45Ta0.45Mo0.10, Nb0.30Ta0.40Mo0.30, Nb0.40Ta0.30Mo0.30, Nb0.30Ta0.30Mo0.40 and Nb0.15Ta0.15Mo0.70 by employing the well-known empty core model potential of Ashcroft for the first time. Five local field correction functions proposed by Hartree, Taylor, Ichimaru-Utsumi, Farid et al. and Sarkar et al. are used in the present investigation to study the screening influence on the aforesaid superconducting properties. The transition temperature TC obtained from the H-local field correction function is found to be in an excellent agreement with the available theoretical data. Also, the present results are found to be in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the superconductors.     

Relativistic Configuration Interaction Treatment of Generalized Oscillator Strength for Krypton

A fully relativistic configuration interaction method is developed to investigate the transition energies and general oscillator strengths of the lower lying states of krypton, for both optically allowed and optically forbidden transitions. The calculated results are in agreement with the recent experimental measurements. The calculated transition energies for the 5s and 5s＇ transitions are 9.970 and 10. 717eV, which agree with the experimental data of 10.033 and 10.643 eV. The calculated oscillator strengths are 0.211 and 0. 170, comparable with the experimental results 0.214（±0.012） and 0.194 （±0.012）, respectively. The momentum transfer positions （K^2 in a.u.） of the minimum and maximum GOSs in the 4s^24p^6 → 4s^24p^5 （5s ＋ 5s＇） transitions are 1.105 and 2.225, comparable with the measurements results 1.24 and 2.97 [Phys. Rev. A 67 （2003） 062708].     

M1 transition energy and rate in the ground configuration of Ag-like ions with 62 ≤ Z ≤ 94

Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ²F^o_5/2,7/2 levels in the ground configuration 4d104f along the Ag-like isoelectronic sequence with 62≤Z≤94 based on the second-order many-body perturbation theory implemented in the Flexible Atomic Code.The electron correlations,Breit interaction and quantum electrodynamics effects are taken into account in the present calculations.The accuracy and reliability of our results are evaluated through comprehensive comparisons with available measurements and other theoretical results.For transition energies,our results are in good agreement with the recent experimental data obtained from the electron beam ion traps within 0.18%.The maximum discrepancy between our results and those obtained with the large-scale multiconfiguration Dirac–Hartee–Fock calculations by Grumer et al.[Phys.Rev.A 89062501(2014)]is less than 0.13%along the isoelectronic sequence.Furthermore,the corresponding M1 transition rates are also reported.The present results can be used as the benchmark and useful for spectra simulation and diagnostics of astrophysical and fusion plasmas.     

Pressure and Temperature Induced Phase Transition of ZnS from First-Principles Calculations

The pressure induced phase transition of ZnS from the wurtzite （WZ） and the zincblende （ZB） structures to the rocksalt （RS） structure and the temperature induced phase transition from the ZB structure to the WZ structure are investigated by ab initio plane-wave pseudopotential density-functional theory （DFT）, together with the quasiharmonic Debye model. It is found that the zero-temperature transition pressures from the WZ-ZnS and the ZB-ZnS to the RS-ZnS are 17.20 and 17.37 GPa, respectively. The zero-pressure transition temperature from the ZB-ZnS to the WZ-ZnS is 1199 K. All these results are consistent with the available experimental data. Moreover, the dependences of the normalized primitive cell volume V/V0 on pressure and thermal expansion coefficient α on temperature are also obtained successfully.     

Molecular dynamics study for the melting curve of MgO at high pressure

Shell-model molecular dynamics method is used to study the melting temperatures of MgO at elevated temperatures and high pressures using interaction potentials. Equations of state for MgO simulated by molecular dynamics are in good agreement with available experimental data. The pressure dependence of the melting curve of MgO has been calculated. The surface melting and superheating are considered in the correction of experimental data and the calculated values, respectively. The results of corrections are compared with those of previous work. The corrected melting temperature of MgO is consistent with corrected experimental measurements. The melting temperature of MgO up to 140GPa is calculated.     

Systematical Study on Ground-State Ionization Potentials for Boron and Carbon Isoelectronic Sequences with Z =6-42

The multi-configuration Dirac-Fock method is used in this work to calculate ground-state ionization potentials of Boron and Carbon isoelectronic sequences from Z = 6 to Z=42. And the contribution of relativistic corrections, nuclear volume effect, Breit and QED effects to tile results is discussed in the calculation. The results are compared with the scanty existing theoretical and experimental data in the literature and good agreements are achieved. Then analytical expressions of lonization potential along Boron and Carbon isoelectronic sequences are obtained.