UV Raman spectra and cross sections of chemical agents

Christesen, Steven D.; Lochner, J. M.; Hyre, Aaron M.; Emge, Darren K.; Jones, Jay Pendell

doi:10.1117/12.669841

Cited by 15 publications

(8 citation statements)

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Section: Experimental Methodsmentioning

confidence: 99%

“…The ideal simulants for Raman detection are those that have spectral characteristics (i.e., Raman spectra, Raman cross-section, and absorption cross-section) as well as physical characteristics (i.e., viscosity and vapor pressure) similar to those of the actual CWAs. 12 A list of chemical agent simulants we have chosen is provided in Table 1. The simulant chemicals, dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), triethyl phosphate (TEP), diethyl malonate (DEM), and methyl salicylate (MES), were purchased from Acros Organics.…”

Section: Simulantsmentioning

confidence: 99%

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Raman Spectroscopic Detection for Simulants of Chemical Warfare Agents Using a Spatial Heterodyne Spectrometer

et al. 2017

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Raman spectroscopic detection is one of the suitable methods for the detection of chemical warfare agents (CWAs) and simulants. Since the 1980s, many researchers have been dedicated to the research of chemical characteristic of CWAs and simulants and instrumental improvement for their analysis and detection. The spatial heterodyne Raman spectrometer (SHRS) is a new developing instrument for Raman detection that appeared in 2011. It is already well-known that SHRS has the characteristics of high spectral resolution, a large field-of-view, and high throughput. Thus, it is inherently suitable for the analysis and detection of these toxic chemicals and simulants. The in situ and standoff detection of some typical simulants of CWAs, such as dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), triethylphosphate (TEP), diethyl malonate (DEM), methyl salicylate (MES), 2-chloroethyl ethyl sulfide (CEES), and malathion, were tried. The achieved results show that SHRS does have the ability of in situ analysis or standoff detection for simulants of CWAs. When the laser power was set to as low as 26 mW, the SHRS still has a signal-to-noise ratio higher than 5 in in situ detection. The standoff Raman spectra detection of CWAs simulants was realized at a distance of 11 m. The potential feasibility of standoff detection of SHRS for CWAs simulants has been proved.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Simulantsmentioning

confidence: 99%

Raman Spectroscopic Detection for Simulants of Chemical Warfare Agents Using a Spatial Heterodyne Spectrometer

et al. 2017

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“…The advantages of this excitation include the appearance of Raman scattering close to the exciting line (in wavelength terms) and displaced from longer wavelength fluorescence; the ability, if desired, to collect Raman and fluorescence data simultaneously; 391 the large n 4 intensity benefit of very short wavelength excitation and the possibility of resonance enhancement; surface detection due to the short penetration of deep-UV radiation into almost every sample; and the use of solar-blind detectors, thus discriminating against ambient light, and allowing operation of the instrument in broad daylight. This technique is attractive for a portable instrument in a number of applications, including military (explosive and chemical detection), [392][393][394][395] safety and security, and field geology, as well as Martian exploration. For the military and safety and security personnel, the ability to perform standoff measurements is enabled by the use of solar-blind detectors and the large n 4 intensity benefit.…”

Section: Raman Spectrometer Technologies and Applicationsmentioning

confidence: 99%

Portable Spectroscopy

Crocombe¹

2018

Appl Spectrosc

374

233

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Until very recently, handheld spectrometers were the domain of major analytical and security instrument companies, with turnkey analyzers using spectroscopic techniques from X-ray fluorescence (XRF) for elemental analysis (metals), to Raman, mid-infrared, and near-infrared (NIR) for molecular analysis (mostly organics). However, the past few years have seen rapid changes in this landscape with the introduction of handheld laser-induced breakdown spectroscopy (LIBS), smartphone spectroscopy focusing on medical diagnostics for low-resource areas, commercial engines that a variety of companies can build up into products, hyphenated or dual technology instruments, low-cost visible-shortwave NIR instruments selling directly to the public, and, most recently, portable hyperspectral imaging instruments. Successful handheld instruments are designed to give answers to non-scientist operators; therefore, their developers have put extensive resources into reliable identification algorithms, spectroscopic libraries or databases, and qualitative and quantitative calibrations. As spectroscopic instruments become smaller and lower cost, ''engines'' have emerged, leading to the possibility of being incorporated in consumer devices and smart appliances, part of the Internet of Things (IOT). This review outlines the technologies used in portable spectroscopy, discusses their applications, both qualitative and quantitative, and how instrument developers and vendors have approached giving actionable answers to non-scientists. It outlines concerns on crowdsourced data, especially for heterogeneous samples, and finally looks towards the future in areas like IOT, emerging technologies for instruments, and portable hyphenated and hyperspectral instruments.

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“…However, they also conclude that the molecules can still be unambiguously identified with good enough resolution (in the order of a cm −1 ). Nagli and Gaft [18] and Christesen et al [19] have also studied near resonance Raman on explosives and chemical agents.…”

Section: Introductionmentioning

confidence: 97%