Studies in molecular dynamics of the friction coefficient and the Lorentz gas
Abstract
Various hard sphere molecular dynamics studies are presented. The first describes a modification of Fick's diffusion law, required whenever long time correlations are present. For the Lorentz gas, the non-Markovan nature of the transport process is shown to correspond to a random walk where, after each step, the particle waits for a time as sampled from a waiting time distribution before making the next move. Second, the mass and size dependence of the friction coefficient as well as its dependence on boundary conditions is discussed. A molecular dynamics method is presented which calculates the infinite-mass friction coefficient of finite size hard-sphere particles. The applicability of hydrodynamics is considered to describe fluctuations in fluids on the molecular level. It is shown that the fluctuations present in a system of hard spheres, when placed between closely spaced parallel hard walls, lead to an acoustical resonance for those wavelengths which correspond to the spacing, or integer fractions thereof.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1979
- Bibcode:
- 1979PhDT........19A
- Keywords:
-
- Lorentz Gas;
- Molecular Diffusion;
- Molecular Interactions;
- Boundaries;
- Boundary Conditions;
- Coefficient Of Friction;
- Diffusion Coefficient;
- Ficks Equation;
- Hydrodynamics;
- Normal Density Functions;
- Resonant Vibration;
- Stokes Law (Fluid Mechanics);
- Atomic and Molecular Physics