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Ashcroft’s empty core (EMC) model potential is used to study the superconducting state parameters (SSPs) viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature T C, isotope effect exponent αand effective interaction strength N O V of some binary metallic glasses based on the superconducting (S), conditional superconducting (S’) and non-superconducting (NS) elements of the periodic table. 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 for the first time with EMC potential in the present investigation to study the screening influence on the aforesaid properties. The T C obtained from the H-local field correction function are in excellent agreement with available theoretical or experimental data. In the present computation, the use of the pseudo-alloy-atom model (PAA) was proposed and found successful. Present work results are in qualitative agreement with such earlier reported experimental values which confirm the superconducting phase in all metallic glasses. A strong dependency of the SSPs of the metallic glasses on the valence ‘Z’ is identified.

We investigated the structure and electronic properties of the compound Mg1-xBixO with varying concentrations of 0, ¼, ½, and ¾ x bismuth in the the cesium chloride (CsCl), zinc-blende (ZnS), nickel arsenide (NiAs) NaCl (rock-salt) and WZ (wurtzite) phases. We calculated. The calculations were performed using the first-principles pseudo-potential method within the framework of spin density functional theory (DFT)., {"references":["G. Patricia Abdel Rahim, J. Arbey Rodriguez y M.G. Moreno Armenta,\n\"Study ab-initio of the stability of the structural and electronic properties\nof Bi1-xMgxO,\" ITECKNE, vol. 11, 2014, pp. 84 – 92.","B. Amrani, R. Ahmed, F. El. Haj. Hassan, \"Structural, electronic and\nthermodynamic properties of wide band gap MgxZn1-xO alloy,\"\nComputational Materials Science, vol.40, 2007, pp. 66-72.","G. Murtanza, I. Ahmad, B. Amin, A. Afaq, F. Ghafoor, A. Benamrani,\n\"Linear and non-linear optical response of MgxZn1-xO: A Density\nFunctional study,\" Physica B: Condensed Matter, vol. 406, 2011, pp.\n2632- 2636.","G. Zhao, H. F. Mu, X. M. Tan, D. H. Wang, C. L. Yang, \"Structural and\ndynamical properties of MgSiO3 melt over the pressure range 200-500\nGPa: Ab initio molecular dynamics,\" Journal of Non-Crystalline Solids,\nvol. 385, 2014, pp. 169-174.","Ph. Hofmann, \"The surfaces of bismuth: Structural and electronic\nproperties,\" Science Direct, vol. 81, 2006, pp. 191-245.","G. Patricia Abdel Rahim, J. Arbey Rodriguez y M.G. Moreno Armenta,\n\"The influence of pressure on the structural and electronic properties of\nBi\"","G. Patricia Abdel Rahim, J. Arbey Rodriguez y M.G. Moreno Armenta,\n\"Transiciones de fases y gap directo – indirecto inducidas por presión en\nMgO: Estudio mediante DFT\" Rev. Cub. Fis. 31 No 1 E, E22 (2014).","P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car, C. Cavazzoni,\nD. Ceresoli, G. L. Chiarotti, M. Cococcioni, I. Dabo, A. D. Corso, S. de Gironcoli, S. Fabris, G. Fratesi, R. Gebauer, U. Gerstmann, C.\nGougoussis, A. Kokalj, M. Lazzeri, L. Martin-Samos, N. Marzari, F.\nMauri, R. Mazzarello, S. Paolini, A. Pasquarello, L. Paulatto, C.\nSbraccia, S. Scandolo, G. Sclauzero, A.P. Seitsonen, A. Smogunov, P.\nUmari, and R. M. Wentzcovitvh, \"Quantum Espresso: a modular and\nftware proyect for quantum simulations of materials\" J. Phys. Condens.\nMatter, 21, 2009, p. 395502. Rev. Acad. Colomb. Cienc., 37 (1), 2013,\npp 47-51.","J. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett.77, 1996, p. 3865.\n[10] K. Laasonen, A. Pasquarello, R. Car, C. Lee, D. Vanderbilt, \"Car-\nParrinello molecular dynamics with Vanderbilt ultrasoft pseudopotentials,\"\nPhysical Review B, vol. 47, 1993, pp. 10142-10153.\n[11] H. J. Monkhorst, J. D. Pack, \"Special points for Brillouin-zone\nintegrations,\" Phys. Rev. B, vol. 13, 1976, pp. 5188-5192.\n[12] M. Methfessel, A.T. Paxon, Phys. Rev. B., 40 (1989), p. 3616.\n[13] F. D. Murnaghan, Proc. Natl. Acad. Sci., USA 30:244, 1994, 49."]}

An attempt has been made to estimate the activity coefficient, γ°_1 of the solute at infinite dilution in metallic solution from fundamental physical constants of constituent elements only, such as volume, packing fraction, and Fermi wave vector for free electrons. This approach is based on a theoretical equation of ln γ°_1=ln γ°_1 (ps)+ln γ°_1 (el)+ln γ°_1 (hs), described by the pseudo-potential term and the electron gas term coupled with the hard sphere term. The calculated results of Al-base and Pb-base solutions indicate the correct sign for and its magnitude is found to be in reasonable agreement with the experimental data. The approximate equation for the pseudo-potential term by using the molar heat of solution at infinite dilution has also been tested, in order to allow simple estimation of the activity coefficient in various metallic solutions. The usefulness of the present theoretical approach with about 85% reliability predicting the correct sign was confirmed by obtaining the reasonable agreement between calculation and the experimental data in 50 cases for non-ferrous solutions, such as Al-base, Pb-base, Cd-base and In-base alloys, and 15 cases in Fe-base solutions. Nevertheless, it should be kept in mind that the present approach does not explicitly include the entropy effect of 3d electrons which is quite likely significant in ferrous solutions., 報文

Energy of electronic subsystem of semi-infinite metal is presented in the form of an expansion in powers of pseudo-potential. It is shown that generally electron many-particle density matrices are necessary for the energy calculation, whereas in case of a local pseudo-potential only diagonal elements (electron distribution functions) are necessary. In a specific case of a local pseudo-potential within the first order of perturbation theory, our results for energy coincide with those widely applicable in the density functional theory. Представлено енергiю електронної пiдсистеми напiвобмеженого металу у виглядi ряду за степенями псевдопотенцiалу. Показано, що в загальному випадку для розрахунку цiєї енергiї необхiднi електроннi багаточастинковi матрицi густини, тодi як у частковому випадку локального псевдопотенцiалу лише її дiагональнi елементи (функцiї розподiлу електронiв). У першому порядку теорiї збурень у випадку локального псевдопотенцiалу наш результат для енергiї спiвпадає iз широко застосовуваними у теорiї функцiоналу густини.

International audience; This paper is concerned with the numerical modeling of three-dimensional contact problems in elastostatics with Coulomb friction and large slips. Two variational formulations called pseudo-potential and bi-potential are presented from an algorithmic point of view. A quantitative comparison is made for the first time between the Newton algorithm and the Uzawa algorithm in the bi-potential framework. A test example is included to demonstrate the developed algorithms and to highlight their performance.; Cet article traite de la modélisation numérique des problèmes de contact avec frottement en élasticité linéaire et en grands glissements. Deux formulations variationnelles appelées respectivement pseudo-potentiels et bi-potentiel sont présentées du point de vue algorithmique. Une comparaison quantative a été menée pour la première fois entre une résolution numérique de type Uzawa et une autre de type Newton dans le cadre du bi-potentiel. Un exemple test est inclus afin d'évaluer les performances des algorithmes développés.

International audience; This paper is concerned with the numerical modeling of three-dimensional contact problems in elastostatics with Coulomb friction and large slips. Two variational formulations called pseudo-potential and bi-potential are presented from an algorithmic point of view. A quantitative comparison is made for the first time between the Newton algorithm and the Uzawa algorithm in the bi-potential framework. A test example is included to demonstrate the developed algorithms and to highlight their performance.; Cet article traite de la modélisation numérique des problèmes de contact avec frottement en élasticité linéaire et en grands glissements. Deux formulations variationnelles appelées respectivement pseudo-potentiels et bi-potentiel sont présentées du point de vue algorithmique. Une comparaison quantative a été menée pour la première fois entre une résolution numérique de type Uzawa et une autre de type Newton dans le cadre du bi-potentiel. Un exemple test est inclus afin d'évaluer les performances des algorithmes développés.

In view of recent experiments on ultra-cold polarized fermions, the zero-range potential approach is generalized to situations where two-body scattering is resonant in the p-wave channel. We introduce a modified scalar product which reveals a deep relation between the geometry of the Hilbert space and the interaction. This formulation is used to obtain a simple interpretation for the transfer rates between atomic and molecular states within a two branches picture of the many-body system close to resonance. At resonance, the energy of the dilute gas is found to vary linearly with density., 4 pages

We construct a many-body Gaussian variational approach for the two-dimensional trapped Bose gas in the condensate phase. Interaction between particles is modelized by a generalized pseudo-potential of zero range that allows recovering perturbative results in the ultra-dilute limit, while back action of non-condensate particles on the condensate part is taken into account for higher density. As an application, we derive the equation of state and solve stability problems encountered in similar mean-field formalisms for a single vortex configuration.

Damage pseudo-potentials, from which the damage evolution equations can be acquired, are usually expressed as scalar functions of irreversible thermodynamic variables. A lower potential for an action with the dissipation property corresponds to a Helmholtz free energy function in classical mechanics; therefore, pseudo-potential acts as a cornerstone of the damage constitutive relationship. According to the analysis on state and process of a damage system, the authors study the connection between damage action, pseudo-potential and free energy function. Next a general method to define the pseudo-potential of damage process is discussed. The discrete elementary equations of continuum damage mechanics are derived from the action functional. Subsequently, the numerical implementation of the aforementioned damage model is given. Comparison between experimental evidences and numerical results verifies the soundness of the theoretical model and the numerical framework.

Some minimum theorems potentially useful to construct numerical schemes related to quasi-static evolution of damage in brittle elastic solids are proposed. The approach is that of multifield theories, with a second-order damage tensor describing the microcrack density. The use of damage entropy flux and damage pseudo-potential are both investigated.