Magnetic properties of Fe, Co, and Ni at finite temperatures have been investigated on the basis first-principles dynamical coherent potential approximation (CPA) combined with local density (LDA) + U Hamiltonian in tight-binding linear muffintin orbital (TB-LMTO) representation. The includes transverse spin fluctuation terms. Numerical calculations performed within harmonic 4th-order corrections. Calculated single-particle densities states ferromagnetic state indicate that effects reduce...

A complex optical potential, in the framework of Dirac partial wave analysis, is employed to study minima differential cross sections (DCSs) and spin polarization due elastic scattering electron by Pb atom. In addition, integral, momentum-transfer, absorption, viscosity total are also reported for energy region 6 eV ≤ Ei ≤10 keV. This potential comprises static, exchange, absorption components. We obtain, total, 12 critical (CM) positions, where DCS attains its smallest values 22 points with...

A theoretical investigation on differential, integral, momentum transfer, viscosity cross sections and spin polarization for elastically scattered electrons positrons from Ar atoms in the energy range 1 eV ≤ Ei 0.5 GeV is presented. In addition, we have studied critical minima elastic differential sections, absorption, total ionization sections. Two different approaches, depending upon incident energy, are employed solving relativistic Dirac equation with partial-wave decomposition. The...

The spin-polarization S and the parameters U T of elastically scattered electrons from Hg atoms have been computed for scattering angles 0°–180° in energy range 1 eV . An optical model approach is employed using a complex potential within framework Dirac relativistic partial wave analysis. We compare our results with recent experiments available theoretical calculations find reasonable agreement over wide energies.

Abstract A simple modification of the revised Deutsch–Märk model (RDM) [Deutsch et al., Int J Mass Spectrom 2004, 233, 13] incorporating both ionic and relativistic corrections is proposed to investigate K ‐shell ionization 30 atomic targets with numbers Z = 1–92 for incident energies up 2 GeV. We also revisit our earlier models: modified Bell (MBELL) (Haque Phys Rev 2006, 73, 012708) Kolbenstvedt (MKLV) (Uddin Eur D 37, 361), cross sections at these ultra‐relativistic energies. The results...

The differential, integrated elastic, total and momentum transfer cross sections along with Sherman function for the elastic scattering of electrons positrons by cadmium atoms have been evaluated from partial wave solution Dirac relativistic equations a projectile-atom complex potential at energy range 6.4 eV < E 1.0 keV. For various quantities, comparison our results exhibits better agreement experimental data than other available theoretical values.

First-principles dynamical coherent-potential approximation for electron correlations has been developed further by taking into account higher-order corrections with use of the asymptotic approximation. The theory is applied to investigations a systematic change in excitation spectra $3d$ transition metals from Sc Cu at finite temperatures. It shown that effects damp main peaks densities states (DOSs) obtained local-density density-functional theory, reduce band broadening due thermal spin...

The differential, integrated elastic, momentum transfer, viscosity and total cross-sections along with Sherman function for the elastic scattering of electrons positrons by sodium atoms have been calculated within framework complex projectile–atom optical potential model at impact energies 0.1 ≤ Ei 104 eV both projectiles. relativistic Dirac partial wave techniques, accurate analytical charge densities, are used to obtain amplitudes. present results produce satisfactory agreement...

We present a theoretical study on the calculations of various cross sections related to scattering electrons and positrons from indium atoms. Our cover energy range 1 eV ⩽Ei⩽0.5 GeV. have employed two approaches, applicable for domains energy, based Dirac partial-wave analysis. In one approach, we used both atomic nuclear potentials calculate low intermediate energies. The other valid high-energy scattering, utilizes only potential phase-shift analysis, considers magnetic nucleus too. report...

The theoretical investigation of differential, integrated elastic, momentum transfer, viscosity, inelastic, grand total and ionisation cross sections along with the Sherman functions for scattering electrons positrons by polar NH3 molecule in energy range 1 eV–1 MeV are reported present work. We carry out calculations using independent atom model (IAM) IAM screening correction. observables calculated a complex optical potential framework Dirac partial wave analysis. application correction to...

Abstract A new semiempirical model comprising few important features of the DM Deutsch et al. (Int J Mass Spectrom 1998, 177, 47) and widely used empirical Bell (J Phys Chem Ref Data 1983, 12, 891) has been proposed. The proposed examined to evaluate electron impact K ‐shell ionization cross sections 30 atomic targets ranging from H U ( Z = 1–92) found describe with considerable success experimental results over a wide range incident energies up 2 GeV using single set species independent...

With a complex optical potential, V(r), the Dirac relativistic equation is solved, employing partial wave technique, to evaluate differential, integrated, momentum transfer and viscosity cross-sections for elastic scattering of e±-Hg system over incident energy range 1.0 eV ≤Ei≤ 10.0 keV. We also calculate inelastic grand total cross sections this same range. The real part V(r) includes static, exchange polarisation components while imaginary component incorporates absorption particles into...

Differential, integral, momentum-transfer, viscosity, inelastic and total cross sections as well spin asymmetries are calculated for electron positron scattering from the gold atom with nuclear 3 2 . The impact energies of projectiles range low-energy atomic physics regime to high-energy physics. This is accomplished by employing two different theoretical approaches, applicable aforesaid domains energies, based on partial-wave analysis. In one approach, phase shifts analysis done at E i < 1...

Abstract We propose an extension of the modified simplified‐improved‐binary‐encounter dipole (MRIBED) model (Uddin et al., Phys Rev A 2005, 72, 032715), incorporating both ionic and relativistic corrections, to investigate K ‐shell ionization atomic targets with numbers Z = 1 − 92 for incident energies up 2 GeV. also revisit our earlier models, MBELL (Haque al. 2006, 73, 012708) MKLV Eur J D 37, 361), at these ultra‐relativistic energies. The results from extended version MRIBED, MBELL,...

We have investigated the magnetic properties of Fe, Co, and Ni at finite temperatures on basis first-principles dynamical coherent potential approximation (CPA) in order to clarify role exchange interaction energy ($J$) screened by $\mathit{sp}$ electrons its applicability finite-temperature magnetism. With use atomic $J$, we obtained Curie (${T}_{C}$) 1930 K for Fe 2550 fcc which are overestimated a factor 1.8 compared with experimental values, while ${T}_{C}=620$ being good agreement...

The variational theory of momentum dependent local-ansatz (MLA) has been generalized by introducing a hybrid (HB) wavefunction as starting wavefunction, whose potential can flexibly change from the Hartree-Fock type to alloy-analogy varying weighting factor zero one. Numerical results based on half-filled band Hubbard model hypercubic lattice in infinite dimensions show up that new yields ground-state energy lower than Gutzwiller (GW) whole Coulomb interaction regime. Calculated double...

Momentum dependent local-ansatz wavefunction approach (MLA) to the correlated electron systems in solids has been further developed solve best a self-consistent equation for variational parameters at non half-filling. With use of improved scheme we performed numerical calculations non-half-filled band Hubbard model on hypercubic lattice infinite dimensions. We verified that significantly improves correlation energy and momentum distribution as compared with original MLA. also demonstrate...

The recently proposed generalized Kolbenstvedt model (GKLV) of Haque et al (2007 Eur. Phys. J. D 42 203), for the electron impact ionization (EII) atoms, was applied to a wide range K-, L- and M-shell electrons ionic targets from threshold 1 MeV incident energy. set species-independent parameters, two each ionized orbits, is same as that neutral targets, provides an excellent account EII cross-sectional data 36 ions, including those belonging Li, Be, B, C, N, O Ne electronic sequences well...

This paper reports on the differential, integral, momentum transfer and viscosity cross sections along with spin polarisation for elastically scattered electrons positrons from iron atoms in incident energy (Ei) range 1≤Ei≤104 eV. In addition, we report here systematically details of critical minima elastic differential sections, absorption total sections. An optical model using a complex potential, composed static, exchange, imaginary terms, is used to solve Dirac relativistic equation...

Momentum dependent local-ansatz (MLA) wavefunction describes accurately electron correlations from the weak to intermediate Coulomb interaction regimes. We point out that MLA can describe strong regimes by modifying starting Hartree–Fock (HF) type an alloy-analogy (AA) wavefunction. Numerical results based on half-filled band Hubbard model hypercubic lattice in infinite dimensions show up new yields ground-state energy lower than Gutzwiller (GW) whole regime. Calculated double occupation...

The wavefunction method provides us with a useful tool to describe electron correlations in solids at the ground state. In this paper we review recent development of momentum-dependent local ansatz (MLA). It is constructed by taking into account two-particle excited states projected onto orbitals, and amplitudes these are chosen as variational parameters. MLA describes accurately correlated from weak intermediate Coulomb interaction regime infinite dimensions, works well even strongly region...