Computational and Theoretical Techniques for Materials Science (1995) / Chapter Skim
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Pages 40-49
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From page 40... ...
identifies below. Among the areas of computational and theoretical materials research represented at NRL are electronic structure calculations, growth phenomena, strongly correlated systems, ferroelectrics, clusters, defects, transport properties, free-energy calculations, phase changes, optical properties, many-bocly theory, algorithm development work on simulations of larger systems, ant!
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From page 41... ...
The intrinsic serial character of molecular dynamics can be avoided only by using Monte CarIo and other intrinsically statistical approaches. The impact of computing technology on molecular dynamics simulations is suggested by the history of the size anti duration of such simulations as shown in Figure 4.2 Although the extremes of time anti length scales cannot yet be reached simultaneously, a large-scale molecular dynamics simulation of fracture in a short-range pair potential mode!
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From page 42... ...
A dramatic increase in computing power will permit enhancement of the incorporation of chemistry (thermochemical accuracyJ into materials callfculations. The incorporation of chemistry into materials calculations will be enhance(1 by dramatic improvements in computer power and algorithmic aclvances.
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From page 43... ...
Although stancIard electronic structure calculations based on the local density functional approximation yield highly accurate structural properties for many systems, they often have clifficulty in describing the properties and phase diagram of highly 43 correlated magnetic systems such as the d- and f-electron materials. Moreover, LDA cohesive energies and energy surfaces (e.g., along reaction paths)
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From page 44... ...
For example, in modeling growth, ab initio calculations lea(1 to interatomic potentials. These are then used in molecular dynamics simulations to obtain rate constants for different categories of interactions.
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The precliction of the optical properties of materials is a particularly challenging task because standard electronic structure methods are typically grouncI-state theories that afforc! poor descriptions of electronic excitations in materials.
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From page 46... ...
This expansion converges fairly rapidly and provides the link between statistical, mechanical, and ah initio quantum mechanical electronic structure studies. A prominent opportunity in this context is the use of electronic structure calculations to contribute to the databases utilized by semiempirical theories of material-phase liagrams, such as CALPHAD.
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From page 47... ...
is still very DETERMINATION OF PHENOMENOLOGICAL INTERACTIONS FROM ELECTRONIC STRUCTURE CALCULATIONS Opportunity 9: Substantial improvements in the determination of phenomenological potentials from electronic structure calculations will be accelerated. The abstraction of phenomenological parameters (i.e., both their formulation ant!
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From page 48... ...
Epilogue Given the rapist pace of change in the computer industry today, it is clear that the details of the computer-related issues in this report will continue to evolve quickly. Advances made in algorithmic design will inexorably lead to scientific progress that will then bring other challenges to the forefront.
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