Absorption of Cyclic Polynitramines in the solid and Solvated States

Marinkas, Paul L.; Mapes, J. E.; Downs, D. S.; Kemmey, P. J.; Forsyth, Arthur C.

doi:10.1080/15421407608084308

Cited by 15 publications

(5 citation statements)

References 10 publications

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“…[3][4][5][6][7][8][9] To develop a quantitative description of the PF/LIF process, it is necessary to know the absorption cross section of the corresponding explosive m aterial in the gas phase. Because of their low vapor pressures and pronounced tendency to decompose at elevated temperatures, the available ultraviolet spectra of nitro compounds have primarily been recorded either in solution 10 -12 or in the solid phase; 12,13 gas-phase spectra are rare. 14 -16 As a part of our efforts 6,7 to detect trace amounts of 2,4,6-trinitrotoluene (TNT) in soil and ground water, we have in the present work m easured the absorption cross section of gaseous TNT in the spectral region from about 195 to 300 nm.…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Gaseous 2,4,6-Trinitrotoluene in the Ultraviolet Region

et al. 2001

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The absorption spectrum of gaseous 2,4,6-trinitrotoluene (TNT) was recorded by conventional absorption spectroscopy (AS) as well as cavity ringdown spectroscopy (CRDS) methods in the spectral regions 195–300 and 225–235 nm, respectively. These spectra were normalized by using the saturated TNT vapor-number density for the measured cell temperature to obtain the absorption cross section of TNT. No spectral features were found in the spectra; this result is consistent with a repulsive electronic excited state of TNT. The temperature dependence of the absorption coefficient of saturated TNT vapor was measured within the temperature range 5–110 °C. The limit of detection of TNT vapor by CRDS is less than 1 ppb. Real-time CRDS measurements of the TNT vapor density at 21 and 37 °C are presented. The TNT evaporation rates were found to be 7 × 108 and 4 × 1010 molecules/cm2 × s at 21 and 37 °C, respectively.

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Section: Introductionmentioning

confidence: 99%

Optical Properties of Gaseous 2,4,6-Trinitrotoluene in the Ultraviolet Region

et al. 2001

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“…The absorption of the RDX molecule dissolved in a solution shows two strong peaks at ~ 5.3 eV and 6.2 eV. [7][8][9] whereas predicted values for the bandgap of the solid state of RDX range from 3.59 eV to 5.9 eV. [10,11] Work by Kukla and Kunz [12] has shown defects of the crystal structure, such as edge dislocations, could lower the bandgap of RDX.…”

Section: Discussionmentioning

confidence: 96%

Optical Absorption Measurements of RDX

Whitley

2006

AIP Conference Proceedings

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Optical absorption measurements on a variety of RDX samples in the 1.38-6.2 eV (200-900nm) wavelength range were undertaken to determine the sample-to-sample variations present in asreceived samples. Samples were also annealed at elevated temperatures and subjected to pressures as high as 20 GPa to determine the effects of temperature and pressure on the optical absorption spectra. A sample-to-sample variation in the optical absorption of as-received samples was found, with the onset of strong absorption occurring at between 3.6eV (345nm) to 4.1eV (280nm). Subjecting RDX to pressures of 0.3-16GPa lowered the onset of strong absorption at 4.1 eV and produced a weak absorption throughout the visible region. Annealing RDX at temperatures of 383 K increased the measured absorption throughout the UV and visible peaking at ~3.4 eV (360nm).

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“…(111,114) In comparison with spectra recorded in acetonitrile solution, the solidstate spectra generally have absorption maxima shifted to longer wavelengths. This effect is attributed to intermolecular stabilization of the energetic molecules in the solid phase.…”

Section: Ultraviolet/visible Absorption Spectroscopymentioning

confidence: 99%

Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

Hummel

Dubroca

2013

Encyclopedia of Analytical Chemistry

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A wide variety of optical‐ and laser‐based techniques have been and are currently being investigated as means of identifying and characterizing explosive materials. These efforts are hampered by the very low volatility of explosive compounds at room temperature and their tendency to ignite at higher temperatures where their vapor pressures are beginning to reach a regime where the species can be readily detected. Traditional, condensed‐phase absorption spectroscopy (both infrared (IR) and ultraviolet/ visible (UV/VIS)) requires larger samples than are frequently available and, although useful as confirmatory techniques, do not provide signatures that enable unique identification of species. The choice of nontraditional techniques for analysis of explosive materials is dependent upon the amount of sample available, the sample matrix, and sample‐imposed constraints upon the measurement. Raman spectroscopy can identify and quantify condensed phase explosive materials, but the detection limit depends upon substrate, excitation wavelength, and illumination area: limits of detection (LODs) vary from 0.05 ng for 2,4,6‐trinitrotoluene (TNT) on glass to 10 µg for nitroglycerin (NG) on silica gel. The other detection techniques considered require volatilization of either the explosive compound itself or more often of characteristic decomposition products, such as NO, NO 2 , or N 2 O. Using IR irradiation, researchers have demonstrated that photoacoustic spectroscopy (PAS) has detection limits ranging from 0.55 ppb (parts per billion) for vapor‐phase NG with 9 mm excitation to 220 ppm (parts per million) for vaporphase 2,4‐dinitrotoluene (DNT) with 6‐µm excitation. IR laser differential absorption detection of dissociation products NO, NO 2 , and/or N 2 O can achieve detection limits of a few picograms. Laser‐induced fluorescence (LIF) detection of the photofragments (typically NO) of explosive compounds yields detection limits in the tens to hundreds of ppb (by weight) range. Low LODs can be achieved using ion detection techniques: resonance‐enhanced multiphoton ionization (REMPI) spectrometry is capable of LODs for detecting vapor‐phase explosives compounds in the hundredths to tens of ppb range; ion mobility spectrometry (IMS) has vapor‐phase detection limits for common explosive compounds of typically 200 pg, but for some species can be significantly lower: for example, 1 pg for TNT.

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Absorption of Cyclic Polynitramines in the solid and Solvated States

Cited by 15 publications

References 10 publications

Optical Properties of Gaseous 2,4,6-Trinitrotoluene in the Ultraviolet Region

Optical Properties of Gaseous 2,4,6-Trinitrotoluene in the Ultraviolet Region

Optical Absorption Measurements of RDX

Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

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