Three dimensional vibrational spectroscopy and shock initiation of hmx

Sun, Yuxiao

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https://hdl.handle.net/2142/95276 Copy

Description

Title

Three dimensional vibrational spectroscopy and shock initiation of hmx

Author(s)

Sun, Yuxiao

Issue Date

2016-09-07

Director of Research (if dissertation) or Advisor (if thesis)

Dlott, Dana

Doctoral Committee Chair(s)

Dlott, Dana

Committee Member(s)

• Gruebele, Martin
• McCall, Ben
• Suslick, Ken

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Spectroscopy
• HMX
• Shock

Abstract

3D spectroscopy was employed to probe and visualize energy flows through molecules from excited parent states. Studies with IR-Raman pump probe spectroscopy show clearly that the characteristics of the vibrational relaxation pathway depend strongly upon the initial excited states. By employing 3D spectroscopy, it is possible to track and visualize relaxation pathways for an entire range of parent states, providing a better understanding of intramolecular energy transfer. Laser driven shocks and sum frequency generation spectroscopy were used to attempt to observe the mechanisms of initiation for HMX. Those first bond breaking events are poorly understood, and much could be learned from experimental observation. Much refinement of the sample design was done, but there was still no events observed by SFG that were clearly attributable to HMX initiation. No broadening or new peaks were observed at all, and no significant loss of SFG intensity occurred besides the expected loss from the destruction of the aluminum substrate. It is possible that a more uniform and better made sample, perhaps along with significantly more laser power, could successfully observe initiation. Flyer driven shocks and emission spectroscopy were used to determine the relative shock sensitivities of delta and beta HMX, as well as investigate the first nanoseconds after shock compression for HMX. While previous studies by the Dlott group have observed interesting phenomena in those first nanoseconds to microseconds after shock, those studies were done on beta HMX. Similar experiments were done on delta HMX, and it exhibits similar behavior initially with a very high temperature spike, though later behavior is not identical.

Graduation Semester

2016-12

Type of Resource

text

Permalink

http://hdl.handle.net/2142/95276

Copyright and License Information

Copyright 2016 Yuxiao Sun

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