Optical, electronic, and dynamical phenomena in the shock compression of condensed matter

Despite the study of shock wave compression of condensed matter for over 100 years, scant progress has been made in understanding the microscopic details. This thesis explores microscopic phenomena in shock compression of condensed matter including electronic excitations at the shock front, a new dynamical formulation of shock waves that links the microscopic scale to the macroscopic scale, and basic questions regarding the role of crystallinity in the propagation of electromagnetic radiation in a shocked material. In Chapter 2, the nature of electronic excitations in crystalline solid nitromethane are examined under conditions of shock compression. Density functional theory calculations are used to determine the crystal bandgap under hydrostatic stress, uniaxial strain, and shear strain for pure and defective materials. In all cases, the bandgap is not lowered enough to produce a significant population of excited states. In Chapter 3, a new multi-scale simulation method is formulated for the study of shocked materials. The method allows the molecular dynamics simulation of the system under dynamical shock conditions for orders of magnitude longer time periods than is possible using the popular non-equilibrium molecular dynamics (NEMD) approach. An example calculation is given for a model potential for silicon in which a computational speedup of 10⁵ is demonstrated. Results of these simulations are consistent with some recent experimental observations. Chapters 4 and 5 present unexpected new physical phenomena that result when light interacts with a shock wave propagating through a photonic crystal.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Reed, Evan J. (Evan John), 1976-

Advisor dc:contributor.advisor

• John D. Joannopoulos.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/16935

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/16935