High-Pressure Characterization of Nitrogen-Rich Bis-triaminoguanidinium Azotetrazolate (TAGzT) by In Situ Raman Spectroscopy

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 117; no. 8; pp. 1737 - 1743
• Main Authors: Behler, K. D, Ciezak-Jenkins, J. A, Sausa, R. C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 28.02.2013
• Subjects: Atomic and molecular physics; Band spectra; Bands; Compressing; Energetic materials; Exact sciences and technology; Frequency shift; Molecular properties and interactions with photons; Molecular spectra; Physical chemistry; Physics; Raman and rayleigh spectra (including optical scattering); Raman spectroscopy; Transforms; Vibrational transition; Raman spectra; Tetrazole derivatives; Phase transformations; Nitrogen heterocycle; Vibrational modes; Line widths; Azo compounds; Guanidines; Comparative study; Bond lengths; High pressure
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp311463g

Compounds rich in nitrogen are attracting significant interest not only because of their high energy content but also because they are potentially more environmentally benign in comparison to conventional energetic materials. Given this interest, it is desirable to understand their molecular composition and structural variations with pressure to derive their stability and determine the conditions in which they transform physically or chemically. In this study, we examine the room-temperature isothermal compression behavior of bis-triaminoguanidinium azotetrazolate (TAGzT) by in situ Raman spectroscopy to pressures near 17 GPa. We assign the characteristic vibrational bands and report the effects of pressure on band intensity, line width, and frequency shift. Two prominent peaks near 1370 and 1470 cm–1 arise from the C–N and NN symmetric stretches, respectively. Overall, the intensity of these bands and others diminishes with pressure, and their spectral linewidths increase monotonically upon compression. The vibrational frequency modes blue shift linearly upon compression, indicating a generalized stiffening of the bonds as the pressure increases. These results, together with micro Raman spectroscopic analyses of the recovered, decompressed samples, suggest that TAGzT does not undergo any phase transitions within this pressure range. We estimate and report the C–N and NN intermolecular bond lengths under compression.