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Many problems in science and engineering require the solution of a long sequence of slowly changing linear systems. We propose and analyze two methods that significantly reduce the total number of matrix-vector products required to solve all systems. We consider the general case where both the matrix and right-hand side change, and we make no assumptions(More)
A generalized solid-state nudged elastic band (G-SSNEB) method is presented for determining reaction pathways of solid-solid transformations involving both atomic and unit-cell degrees of freedom. We combine atomic and cell degrees of freedom into a unified description of the crystal structure so that calculated reaction paths are insensitive to the choice(More)
Transition-metal alloyed nanoparticles with core-shell features (shell enrichment by one of the metals) are becoming ubiquitous, from (electro-)catalysis to biomedical applications, due to their size control, performance, biocompatibility, and cost. We investigate 132 binary-alloyed nanoparticle systems (groups 8 to 11 in the Periodic Table) using density(More)
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu– xAl ͑x = 0, 5.0, and 8.3 at. %͒ alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic ␥ us and twin ␥ ut stacking fault energies ͑SFEs͒. Our results reveal an increased tendency of Cu–Al to deform preferentially by(More)
In alloys cluster expansions (CE) are increasingly used to combine first-principles electronic-structure calculations and Monte Carlo methods to predict thermodynamic properties. As a basis-set expansion in terms of lattice geometrical clusters and effective cluster interactions, the CE is exact if infinite, but is tractable only if truncated. Yet until now(More)
For solid-solution Ba1-xKxFe2As2 Fermi surface evolution is mapped via Bloch spectral functions calculated using density functional theory implemented in Korringa-Kohn-Rostoker multiple scattering theory with the coherent-potential approximation. Spectral functions reveal electronic dispersion, topology, orbital character, and broadening (electron-lifetime(More)
Hydrogen is a ubiquitous element that enters materials from many different sources. It almost always has a deleterious effect on mechanical properties. In non-hydride-forming systems, research to date has identified hydrogen-enhanced localized plasticity and hydrogen-induced decohesion as two viable mechanisms for embrittlement. However, a fracture(More)
The host-guest interaction between metal ions (Pt(2+) and Cu(2+) ) and a zirconium metal-organic framework (UiO-66-NH2 ) was explored using dynamic nuclear polarization-enhanced (15) N{(1) H} CPMAS NMR spectroscopy supported by X-ray absorption spectroscopy and density functional calculations. The combined experimental results conclude that each Pt(2+)(More)