The EOS of α-NTO through high-pressure microscopy-interferometry measurements

Elissaios Stavrou, Joseph M. Zaug, Sorin Bastea, Jonathan C. Crowhurst, Harry B. Radousky, Michael R. Armstrong

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Measuring the volume of a material compressed quasi-statically to a high-pressure typically involves the determination of a primitive crystal cell volume using x-ray diffraction (XRD) techniques. The accumulation of pressure dependent volumes leads to an understanding of the material's equation of state, (EOS); however, in the case of low-symmetry (e.g. triclinic) materials with twining features, and large primitive cells, conventional XRD approaches can be technically problematic and lead to ambiguous or mathematically under-determined lattice constants. To resolve this long-standing issue, we examined the utility of a "direct" approach toward determining a material's volume by measuring surface area and sample height using optical microscopy and interferometry respectively. To test the validity of our proposed approach, we first compared our results from pressurized Triamino-Trinitrobenzene (TATB, SG P-1) with a published EOS determined by synchrotron XRD measurements of Stevens et al. A near-perfect match between the two sets of V(P, 300K) data is observed; and thus, we proceeded to determine the EOS of the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one (α-NTO), which under ambient conditions crystallizes as a fourcomponent twinned system with a triclinic symmetry (SG P-1). No high-pressure XRD EOS data have been published on α-NTO, probably due to its unambiguously complex crystal structure. The results of this study reveal that our proposed approach applied to quasi-statically compressed anisotropic materials is a reliable alternative toward determining material EOSs,-especially when conventional methodologies are not feasible.

Original languageEnglish
Title of host publicationShock Compression of Condensed Matter - 2015
Subtitle of host publicationProceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter
EditorsRamon Ravelo, Thomas Sewell, Ricky Chau, Timothy Germann, Ivan I. Oleynik, Suhithi Peiris
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735414570
StatePublished - 13 Jan 2017
Externally publishedYes
Event19th Biennial American Physical Society Conference on Shock Compression of Condensed Matter, SCCM 2015 - Tampa, United States
Duration: 14 Jun 201519 Jun 2015

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference19th Biennial American Physical Society Conference on Shock Compression of Condensed Matter, SCCM 2015
Country/TerritoryUnited States


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