Etude des conditions d'initiation de la pentrite (PETN) par spectrométrie raman ultra‐rapide

Tailleur, M. H.; Cherville, J.

doi:10.1002/prep.19820070107

Cited by 9 publications

(6 citation statements)

References 10 publications

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“…These data are unable to differentiate if CO 2 is being generated from chemical reactions in our experiment or if absorptions change based on ambient concentration changes in the long path length of air the MIR traverses. The pressure shifted behavior in this experiment is small compared to static high pressure experiments where pressure shifts were measured to be 2 cm –1 /GPa for the ν s -NO 2 and 0.9–3.18 cm –1 /GPa for ν a -NO 2 ; − , however, this phenomenon is commonly observed with the increased temperature in a dynamic experiment. ,,,− Similar comparisons of shocked spectra are shown in Figure for the high frequency region.…”

Section: Resultssupporting

confidence: 55%

“…Focusing specifically on chemistry measurements, the results from Ng et al are of particular interest: they suggest NO 2 elimination is dominant at slow heating rates, NO 3 elimination is dominant at fast heating rates, and C–C bond cleavage is dominant during high energy fracture mechanisms similar to explosively driven impactors or gas guns . A similar result was found by Tailleur et al through nanosecond Raman spectroscopy . Results from Dreger et al and Grudzkov et al suggested NO 3 – elimination and subsequent NO 2 + formation as important intermediate reactions in gas gun ring up shock experiments. ,,, Modeling suggests similar chemical paths to the experimental list above: NO 2 scission, − ,, NO 3 scission, ,, NO formation, HONO elimination, H-ion formation, O-radical formation, C–C bond cleavage, or CH 2 ONO 2 formation .…”

Section: Introductionmentioning

confidence: 75%

“…Several mechanisms have been proposed, including NO 2 scission, − NO 3 scission, ,, HNO 3 formation, HONO elimination, C–C bond cleavage, or CH 2 ONO 2 formation . Further, these mechanisms could potentially be influenced by conformational or phase changes, ,,− or vibrational transfer and electronic structure changes . Focusing specifically on chemistry measurements, the results from Ng et al are of particular interest: they suggest NO 2 elimination is dominant at slow heating rates, NO 3 elimination is dominant at fast heating rates, and C–C bond cleavage is dominant during high energy fracture mechanisms similar to explosively driven impactors or gas guns .…”

Section: Introductionmentioning

confidence: 99%

“…41 Further, these mechanisms could potentially be influenced by conformational or phase changes, 15,16,46−52 or vibrational transfer and electronic structure changes. 53 Focusing specifically on chemistry measurements, the results from Ng et al are of particular interest: they suggest NO 2 elimination is dominant at slow heating rates, NO 3 elimination is dominant at fast heating rates, and C−C bond cleavage is dominant during high energy fracture mechanisms similar to explosively driven impactors or gas guns. 41 A similar result was found by Tailleur et al through nanosecond Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…41 A similar result was found by Tailleur et al through nanosecond Raman spectroscopy. 53 39,42,44,54 Modeling suggests similar chemical paths to the experimental list above: NO 2 scission, [34][35][36]55,56 NO 3 scission, 36,38,56 NO formation, 37 HONO elimination, 34 H-ion formation, 36 O-radical formation, 36 C−C bond cleavage, or CH 2 ONO 2 formation. 36 Determination of the dominant mechanism under shock conditions requires diagnostics with chemical specificity coupled to experiments with resolution commensurate to reactive chemical time and length scales.…”

Section: Introductionmentioning

confidence: 99%

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Insight into the Chemistry of PETN Under Shock Compression Through Ultrafast Broadband Mid-Infrared Absorption Spectroscopy

et al. 2020

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Thin films of pentaerythritol tetranitrate (PETN) were shock compressed using the laser driven shock apparatus at Los Alamos National Laboratory (LANL). Two spectroscopic probes were available to this apparatus: visible white light transient absorption spectroscopy (VIS) from 400 to 700 nm and midinfrared transient absorption spectroscopy (MIR) from 1150 to 3800 cm −1 . Important PETN vibrational modes are the symmetric and antisymmetric NO 2 stretches at 1280 and 1650 cm −1 , respectively, as well as CH stretches at ∼2900 cm −1 . Shock strength was varied from approximately 3 to 55 GPa to span from the chemically unreactive regime to the regime in which fast chemical reaction took place on the 250 ps time scale of the measurements. VIS and MIR results suggest irreversible chemistry was induced in PETN at pressures above 30 GPa. At lower shock pressures, the spectroscopy showed minimal changes attributable to pressure induced effects. Under the higher-pressure reactive conditions, the frequency region at the antisymmetric NO 2 stretch mode had a significantly increased absorption while the region around the symmetric NO 2 stretch did not. No observable increased absorption occurred in the higher frequency regions where CH-, NH-, and OH-bond absorptions would be observed. A broad absorption appeared on the shoulder at the red-edge of the CO 2 vibrational band around 2200 cm −1 . In addition to the experiments, reactive molecular dynamics were carried out under equivalent shock conditions to correlate the evolution of the infrared spectrum to molecular processes. The simulations show results consistent to experiments up to 30 GPa but suggest that NO and NO 2 related features provided the strongest contributions to the shocked infrared changes. Proposed mechanisms for shocked PETN chemistry are analyzed as consistent or inconsistent with the data presented here. Our experimental data suggests C≡O or N 2 O bond formation, nitrite formation, and absence of significant hydroxyl or amine concentrations in the initial chemistry steps in PETN shocked above 30 GPa.

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