John W. Wilkins

Learn More
The combination of long-time, tight-binding molecular dynamics and real-time multiresolution analysis techniques reveals the complexity of small silicon interstitial defects. The stability of identified structures is confirmed by ab initio relaxations. The majority of structures were previously unknown, demonstrating the effectiveness of the approach. A(More)
  • Hyoungki Park, Michael R Fellinger, Thomas J Lenosky, William W Tipton, Dallas R Trinkle, Sven P Rudin +3 others
  • 2012
Density-functional theory energies, forces, and elastic constants determine the parametrization of an empirical, modified embedded-atom method potential for molybdenum. The accuracy and transferability of the potential are verified by comparison to experimental and density-functional data for point defects, phonons, thermal expansion, surface and stacking(More)
I mpurities control phase stability and phase transformations in natural and man-made materials, from shape-memory alloys 1 to steel 2 to planetary cores 3. Experiments and empirical databases are still central to tuning the impurity eff ects. What is missing is a broad theoretical underpinning. Consider, for example, the titanium martensitic(More)
Many-body levels of optically excited and multiply charged InAs nanocrystals are studied with the semi-empirical tight-binding model. Single-particle levels of unstrained spherical InAs nanocrystals are described by the sp 3 d 5 s* nearest-neighbor tight-binding model including spin-orbit coupling. For optically excited InAs nanocrystals, first-order(More)
The electron-hole states of semiconductor quantum dots are investigated within the framework of empirical tight-binding descriptions for Si, as an example of an indirect-gap material, and InAs and CdSe as examples of typical III-V and II-VI direct-gap materials. We significantly improve the energies of the single-particle states by optimizing tight-binding(More)
  • 1