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649 results on '"Krotscheck, E"'

161. Nonlocal screening in metal surfaces

Author

Krotscheck, E and Kohn, W

Subjects
Inorganic And Physical Chemistry
Abstract

Due to the effect of the nonuniform environment on the static screening of the Coulomb potential, the local-density approximation for the particle-hole interaction is found to be inadequate to determine the surface energy of simple metals. Use of the same set of single-particle states, and thus the same one-body density and the same work function, has eliminated the single-electron states in favor of the structure of the short-ranged correlations as the basis of this effect. A posteriori simplifications of the Fermi hypernetted-chain theory may be found to allow the same calculational accuracy with simpler computational tools.

Published
1986
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173. Dynamic many-body theory: Multiparticle fluctuations and the dynamic structure of 4He.

Author

Campbell, C. E., Krotscheck, E., and Lichtenegger, T.

Subjects
*DENSITY functional theory, *DENSITY functionals, *PHENOMENOLOGY, *MOTION, *DYNAMICS
Abstract

We present further progress in a systematic approach to the microscopic understanding of the dynamics of strongly interacting quantum fluids. Employing the concept of dynamic multiparticle fluctuations, we derive equations of motion for fluctuating n-body densities. We apply the theory to calculate the dynamic structure function of liquid He as a function of density and find, without any phenomenological input, overall excellent agreement with both experiments and, as far as available, simulation data. [ABSTRACT FROM AUTHOR]

Published
2015
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174. Dynamic Many-Body Theory: Dynamic Structure Factor of Two-Dimensional Liquid $$^4$$ He.

Author

Krotscheck, E. and Lichtenegger, T.

Subjects
MANY-body problem, STRUCTURAL dynamics, LIQUID helium, PHONONS, SOLID-liquid interfaces, PHASE transitions
Abstract

We calculate the dynamic structure function of two-dimensional liquid $$^4$$ He at zero temperature employing a quantitative multi-particle fluctuations approach up to infinite order. We observe a behavior that is qualitatively similar to the phonon-maxon-roton-curve in 3D, including a Pitaevskii plateau (Pitaevskii, Sov. Phys. JETP 9:830, ). Slightly below the liquid-solid phase transition, a second weak roton-like excitation evolves below the plateau. [ABSTRACT FROM AUTHOR]

Published
2015
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198. TWO-PARTICLE-TWO-HOLE EXCITATIONS IN ³He.

Author

KROTSCHECK, E., BOHM, H. M., and SCHORKHUBER, K.

Subjects
FERMI energy, PHASE transitions, ELECTRONS, DENSITY functional theory, QUANTUM statistics
Published
2006

200. Dynamics of confined quantum fluids

Author

Krotscheck, E., Apaja, V., Krotscheck, E., and Apaja, V.

Abstract

We examine the static and dynamic properties of liquid 4He in confined geometries. Confinement is modeled by placing the liquid between two rigid, attractive walls with strengths corresponding to Geltech, Vycor, or glass. The liquid arranges itself in a series of layers, with increasing areal density it undergoes a sequence of layering transitions familiar from classical fluids. We identify “bulk” excitations that propagate throughout the film, and “layer” excitations that propagate only close to the substrate. Both have the typical phonon-roton dispersion relation, but the energy of the layer-roton minimum depends sensitively on the substrate strength, thus providing a mechanism for a direct measurement of this quantity. Bulk-like roton excitations are largely independent of the interaction between the matrix and the helium atoms. While the bulk-like rotons are very similar to their true bulk counterparts, the layer modes are not in close relation to two-dimensional rotons and should be regarded as a completely independent kind of excitation.

Published
2007
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