Vibrational spectra and structure of RDX and its 13C- and 15N-labeled derivatives: A theoretical and experimental study

Infante-Castillo, Ricardo; Pacheco‐Londoño, Leonardo C.; Hernández‐Rivera, Samuel P.

doi:10.1016/j.saa.2010.02.051

Cited by 41 publications

(48 citation statements)

References 17 publications

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“…RDX has known absorption features in the wavelength tuning range of the QCL, attributed to nitrogen-nitro stretching vibrations, carbon-hydrogen out of plane bending vibrations, and nitrogen-carbon-nitrogen stretching vibrations. 40 There is very good agreement between the photoacoustic and FT-IR reference spectra. There are differences in relative peak intensity between the photoacoustic spectra collected for RDX and the spectra collected with the FT-IR.…”

Section: Resultsmentioning

confidence: 69%

Standoff Photoacoustic Spectroscopy of Explosives

2016

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Detection and identification of unknown and possibly hazardous materials is a vital area of research to which infrared (IR) spectroscopy is ideally suited. Infrared absorption spectra can be measured with many sensing paradigms of which photoacoustic spectroscopy (PAS) is a sensitive and flexible variant. The flexibility of PAS allows for the construction of narrowly tailored spectroscopic sensors that are designed for specific tasks. We discuss the evaluation of an interferometric PAS sensor by the measurement of common explosive hazards from a standoff distance of 1 m. Reproduction of IR absorption spectra for 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), pentaerythritol tetranitrate (PETN), and 2,4,6-trinitrotoluene (TNT) demonstrate the capabilities of the interferometric sensor for standoff explosives detection.

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Section: Resultsmentioning

confidence: 69%

Standoff Photoacoustic Spectroscopy of Explosives

2016

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“…Keeping in mind that the RDX chemical formula can be written as (CH 2 -N-NO 2 ) 3 , the observed transitions in this region involved an admixture of CH 2 bending and N-NO 2 stretching. 26 Comparing the RDX spectrum to the CO 2 laser tuning curve in Fig. 2(a), we decided to conduct thermal imaging measurements at two LWIR wavenumbers where the RDX absorption was stronger or weaker, i.e., 949.5 cm −1 and 973.3 cm −1 , respectively (indicated by the arrows in Fig.…”

Section: A Rdx Lwir Absorptionmentioning

confidence: 99%

Hot spots in energetic materials generated by infrared and ultrasound, detected by thermal imaging microscopy

Chen

You

Suslick

et al. 2014

Review of Scientific Instruments

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We have observed and characterized hot spot formation and hot-spot ignition of energetic materials (EM), where hot spots were created by ultrasonic or long-wavelength infrared (LWIR) exposure, and were detected by high-speed thermal microscopy. The microscope had 15-20 μm spatial resolution and 8.3 ms temporal resolution. LWIR was generated by a CO2 laser (tunable near 10.6 μm or 28.3 THz) and ultrasound by a 20 kHz acoustic horn. Both methods of energy input created spatially homogeneous energy fields, allowing hot spots to develop spontaneously due to the microstructure of the sample materials. We observed formation of hot spots which grew and caused the EM to ignite. The EM studied here consisted of composite solids with 1,3,5-trinitroperhydro-1,3,5-triazine crystals and polymer binders. EM simulants based on sucrose crystals in binders were also examined. The mechanisms of hot spot generation were different with LWIR and ultrasound. With LWIR, hot spots were most efficiently generated within the EM crystals at LWIR wavelengths having longer absorption depths of ∼25 μm, suggesting that hot spot generation mechanisms involved localized absorbing defects within the crystals, LWIR focusing in the crystals or LWIR interference in the crystals. With ultrasound, hot spots were primarily generated in regions of the polymer binder immediately adjacent to crystal surfaces, rather than inside the EM crystals.

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“…27,28 RDX has known absorption features in this region, assigned to nitrogen-nitro stretching vibrations, carbon-hydrogen out of plane bending vibrations, and nitrogen-carbon-nitrogen stretching vibrations. 29 For both species, there is very good agreement between the photoacoustic and FTIR spectra. There are differences in relative peak intensity between the photoacoustic spectra collected for acetone and RDX and the spectra collected with the FTIR.…”

Section: Spectroscopic Datamentioning

confidence: 71%

Photoacoustic spectroscopy for trace vapor detection and standoff detection of explosives

2016

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The Army is investigating several spectroscopic techniques (e.g., infrared spectroscopy) that could allow for an adaptable sensor platform. Current sensor technologies, although reasonably sized, are geared to more classical chemical threats, and the ability to expand their capabilities to a broader range of emerging threats is uncertain. Recently, photoacoustic spectroscopy (PAS), employed in a sensor format, has shown enormous potential to address these ever-changing threats. PAS is one of the more flexible IR spectroscopy variants, and that flexibility allows for the construction of sensors that are designed for specific tasks.PAS is well suited for trace detection of gaseous and condensed media. Recent research has employed quantum cascade lasers (QCLs) in combination with MEMS-scale photoacoustic cell designs. The continuous tuning capability of QCLs over a broad wavelength range in the mid-infrared spectral region greatly expands the number of compounds that can be identified. We will discuss our continuing evaluation of QCL technology as it matures in relation to our ultimate goal of a universal compact chemical sensor platform. Finally, expanding on our previously reported photoacoustic detection of condensed phase samples, we are investigating standoff photoacoustic chemical detection of these materials. We will discuss the evaluation of a PAS sensor that has been designed around increasing operator safety during detection and identification of explosive materials by performing sensing operations at a standoff distance. We investigate a standoff variant of PAS based upon an interferometric sensor by examining the characteristic absorption spectra of explosive hazards collected at 1 m.

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Vibrational spectra and structure of RDX and its 13C- and 15N-labeled derivatives: A theoretical and experimental study

Cited by 41 publications

References 17 publications

Standoff Photoacoustic Spectroscopy of Explosives

Standoff Photoacoustic Spectroscopy of Explosives

Hot spots in energetic materials generated by infrared and ultrasound, detected by thermal imaging microscopy

Photoacoustic spectroscopy for trace vapor detection and standoff detection of explosives

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