Molecular dynamics of supercritical fluids
Abstract/Contents
- Abstract
- Supercritical fluids have received renewed interest in the past few decades because of their industrial applications. Underlying many of these applications is the high tunability of the fluid properties in the near-critical region, which is not captured by the widely held notion of the supercritical state as a single broad continuum. In fact, recent works show that the supercritical region can be divided into liquid-like and gas-like states based on thermodynamic and transport properties with a rapid crossover at the Widom line. However, the picture is less clear when it comes to the microscopic dynamics due to a lack of experimental data and physical understanding of the molecular-scale dynamics in the supercritical state. This dissertation focuses on this problem and contains two main parts. In the first part, a combination of inelastic X-ray scattering measurements and molecular dynamics (MD) simulations is used to study supercritical water. The results show that, contrary to commonly used models, there exist two components in the intermolecular dynamics, and it is the ratio between them that changes rapidly at the Widom line and drives the liquid-like to gas-like transition. In the second part, three additional systems—silicon, tellurium, and the Lennard-Jones fluid—are investigated via MD simulations, and the two-component behavior is found to be universal among these systems. The fraction of the liquid-like component is quantified and found to correlate with the degree of intermolecular bonding. The consequences of the two-component phenomenon for modeling supercritical fluid properties will be discussed.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Sun, Peihao |
|---|---|
| Degree supervisor | Doniach, S |
| Degree supervisor | Hastings, Jerome, 1948- |
| Thesis advisor | Doniach, S |
| Thesis advisor | Hastings, Jerome, 1948- |
| Thesis advisor | Reis, David A, 1970- |
| Degree committee member | Reis, David A, 1970- |
| Associated with | Stanford University, Department of Physics |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Peihao Sun. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/nb187nk1548 |
Access conditions
- Copyright
- © 2021 by Peihao Sun
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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