Atomic motion from the mean square displacement in a monatomic liquid
| Autor: | Giulia De Lorenzi-Venneri, Duane C. Wallace, Eric D. Chisolm |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Physics
Statistical Mechanics (cond-mat.stat-mech) FOS: Physical sciences 02 engineering and technology Statistical mechanics 021001 nanoscience & nanotechnology Condensed Matter Physics Random walk 01 natural sciences Potential energy Mean squared displacement Vibration symbols.namesake Molecular dynamics Classical mechanics Normal mode 0103 physical sciences symbols General Materials Science 010306 general physics 0210 nano-technology Hamiltonian (quantum mechanics) Condensed Matter - Statistical Mechanics |
| Zdroj: | Journal of physics. Condensed matter : an Institute of Physics journal. 28(18) |
| ISSN: | 1361-648X |
| Popis: | V-T theory is constructed in the many-body Hamiltonian formulation, and differs at the foundation from current liquid dynamics theories. In V-T theory the liquid atomic motion consists of two contributions, normal mode vibrations in a single representative potential energy valley, and transits, which carry the system across boundaries between valleys. The mean square displacement time correlation function (the MSD) is a direct measure of the atomic motion , and our goal is to determine if the V-T formalism can produce a physically sensible account of this motion. We employ molecular dynamics (MD) data for a system representing liquid Na, and find the motion evolves in three successive time intervals: On the first "vibrational" interval, the vibrational motion alone gives a highly accurate account of the MD data; on the second "crossover" interval, the vibrational MSD saturates to a constant while the transit motion builds up from zero; on the third "random walk" interval, the transit motion produces a purely diffusive random walk of the vibrational equilibrium positions. This motional evolution agrees with, and adds refinement to, the MSD atomic motion as described by current liquid dynamics theories. Comment: 5 pages, 5 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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