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Self-Consistent Modification To The Electron Density Of States Due To Electron-Phonon Coupling In Metals, Fatih Dogan, Frank Marsiglio
Self-Consistent Modification To The Electron Density Of States Due To Electron-Phonon Coupling In Metals, Fatih Dogan, Frank Marsiglio
Materials Science and Engineering Faculty Research & Creative Works
The "standard" theory of a normal metal consists of an effective electron band which interacts with phonons and impurities. The effects due to the electron-phonon interaction are often delineated within the Migdal approximation; the properties of many simple metals are reasonably well described with such a description. On the other hand, if the electron-phonon interaction is sufficiently strong, a polaron approach is more appropriate. The purpose of this paper is to examine to what degree the Migdal approximation is self-consistent, as the coupling strength increases. We find that changes in the electron density of states become significant for very large …
Effects Of Solvent Model Flexibility On Aqueous Electrolyte Behavior Between Electrodes, Richard L. Rowley, John N. Harb, Clint G. Guymon, Matthew L. Hunsaker, Douglas Henderson
Effects Of Solvent Model Flexibility On Aqueous Electrolyte Behavior Between Electrodes, Richard L. Rowley, John N. Harb, Clint G. Guymon, Matthew L. Hunsaker, Douglas Henderson
Faculty Publications
Molecular dynamics simulations have been carried out for aqueous electrolyte solutions between model electrode surfaces. The effect of solvent model flexibility on bult and double layer properties was observed for electrode surface charge densities of 0, 0.1 and 0.2 and ion concentrations of 0, 0.5 and 1 M. Two flexible models were used to isolate the effects of flexibility from the effects of a change in the condensed-phase dipole moment. Model flexibility increases the pure water self-diffusion coefficient while a larger liquid diple moment substantially decreases it. There is an increase in ion contact adsorption and counter ion affinity with …
Temperature Dependence Of Droplet Nucleation In A Yukawa Fluid, Jinsong Li, Gerald Wilemski
Temperature Dependence Of Droplet Nucleation In A Yukawa Fluid, Jinsong Li, Gerald Wilemski
Physics Faculty Research & Creative Works
We have studied the temperature dependence of gas-to-liquid nucleation in Yukawa fluids with gradient theory and density functional theory. Each of these nonclassical theories exhibits a weaker (i.e., better) temperature dependence than classical nucleation theory. At fixed temperature, the reversible work to form a critical nucleus found from gradient theory approaches the value given by density functional theory as the supersaturation increases. At high temperatures, the two theories remain quite close over a wide range of vapor densities. As the temperature is reduced, the difference between the two theories increases with decreasing vapor density. Compared to the classical theory we …
Tethered Nano Building Blocks: Toward A Conceptual Framework For Nanoparticle Self-Assembly, Zhenli Zhang, Mark A. Horsch, Monica H. Lamm, Sharon C. Glotzer
Tethered Nano Building Blocks: Toward A Conceptual Framework For Nanoparticle Self-Assembly, Zhenli Zhang, Mark A. Horsch, Monica H. Lamm, Sharon C. Glotzer
Monica H. Lamm
We perform molecular simulations to study the self-assembly of nanoparticles functionalized with oligomeric tethers attached to specific locations on the nanoparticle surface. We demonstrate that for certain categories of tethered nano building blocks the obtained morphologies may be predicted using concepts from block copolymer microphase separation and liquid-crystal phase ordering, whereas for other categories the unique packing constraints introduced by nanoparticle geometry and by nanoparticle-tether topology lead to structures far richer than those found in conventional block copolymer, surfactant, and liquid-crystal systems. Our results suggest the potential usefulness of considering tethered nano building blocks as a new class of "macromolecule" …
Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala
Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala
LSU Master's Theses
A scalable parallel algorithm, Macro-Molecular Dynamics (MMD), has been developed for large-scale molecular dynamics simulations of organic macromolecules, based on space-time multi-resolution techniques and dynamic management of distributed lists. The algorithm also includes the calculation of long range forces using Fast Multipole Method (FMM). FMM is based on the octree data structure, in which each parent cell is divided into 8 child cells and this division continues until the cell size is equal to the non-bonded interaction cutoff length. Due to constant number of operations performed at each stage of the octree, the FMM algorithm scales as O(N). Design and …
Massively Parallel Molecular Dynamics Simulations Of Crack-Front Dynamics And Morphology In Amorphous Nanostructured Silica, Cindy Lynn Rountree
Massively Parallel Molecular Dynamics Simulations Of Crack-Front Dynamics And Morphology In Amorphous Nanostructured Silica, Cindy Lynn Rountree
LSU Doctoral Dissertations
Atomistic aspects of dynamic fracture in amorphous and nanostructured silica are herein studied via Molecular dynamics (MD) simulations, ranging from a million to 113 million atom system. The MD simulations were performed on massivelly parallel computers using highly efficient multi-resolution algorithms. Crack propagation in these systems is accompanied by nucleation and growth of nanometer scale cavities up to 20 nm ahead of the crack front. Cavities coalesce and merge with the advancing crack to cause mechanical failure. Recent AFM studies in silica glasses confirm this scenario of fracture [1]. The morphology of the fracture surfaces is studied by calculating the …
Molecular-Dynamics Simulations Of Self-Assembled Monolayers (Sam) On Parallel Computers, Satyavani Vemparala
Molecular-Dynamics Simulations Of Self-Assembled Monolayers (Sam) On Parallel Computers, Satyavani Vemparala
LSU Doctoral Dissertations
The purpose of this dissertation is to investigate the properties of self-assembled monolayers, particularly alkanethiols and Poly (ethylene glycol) terminated alkanethiols. These simulations are based on realistic interatomic potentials and require scalable and portable multiresolution algorithms implemented on parallel computers. Large-scale molecular dynamics simulations of self-assembled alkanethiol monolayer systems have been carried out using an all-atom model involving a million atoms to investigate their structural properties as a function of temperature, lattice spacing and molecular chain-length. Results show that the alkanethiol chains tilt from the surface normal by a collective angle of 25o along next-nearest neighbor direction at 300K. At …