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Feng S, Guo F, Yuan C, Cheng X, Wang Y, Zhang H, Chen J, Su L. Effect of neutron irradiation on structure and decomposition of α-RDX: a ReaxFF molecular dynamics study. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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2
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Singh SK, Vuppuluri V, Sun BJ, Chang BY, Eckhardt AK, Son SF, Chang AHH, Kaiser RI. Identification of Elusive Keto and Enol Intermediates in the Photolysis of 1,3,5-Trinitro-1,3,5-Triazinane. J Phys Chem Lett 2021; 12:6062-6069. [PMID: 34169725 DOI: 10.1021/acs.jpclett.1c01610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Enols have emerged as critical reactive intermediates in combustion processes and in fundamental molecular mass growth processes in the interstellar medium, but the elementary reaction pathways to enols in extreme environments, such as during the decomposition of molecular energetic materials, are still elusive. Here, we report on the original identification of the enol and keto isomers of oxy-s-triazine, as well as its deoxygenated derivative 1,3,5-triazine, formed in the photodecomposition processes of 1,3,5-trinitro-1,3,5-triazinane (RDX)-a molecular energetic material. The identification was facilitated by exploiting isomer-selective tunable photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS) in conjunction with quantum chemical calculations. The present study reports the first experimental evidence of an enol intermediate in the dissociation domain of a nitramine-based energetic material. Our investigations suggest that the enols like 1,3,5-triazine-2-ol could be the source of hydroxyl radicals, and their inclusion in the theoretical models is important to understand the unprecedented chemistry of explosive materials.
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Affiliation(s)
- Santosh K Singh
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Vasant Vuppuluri
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Bo-Yu Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - André K Eckhardt
- Department of Chemistry, MIT, Cambridge, Massachusetts 02139, United States
| | - Steven F Son
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Agnes H H Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
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Study on the Photolysis Route of Nano 2,2ʹ,4,4ʹ,6,6ʹ–Hexanitrostillbene by Vibrational Spectroscopy. JOURNAL OF ANALYSIS AND TESTING 2021. [DOI: 10.1007/s41664-021-00184-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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A vacuum ultraviolet photoionization study on the isomerization, decomposition, and molecular mass growth processes in solid nitromethane (CH3NO2). Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Singh SK, Vuppuluri V, Son SF, Kaiser RI. Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX). J Phys Chem A 2020; 124:6801-6823. [DOI: 10.1021/acs.jpca.0c05726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Santosh K. Singh
- Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
| | - Vasant Vuppuluri
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Steven F. Son
- Mechanical Engineering, Purdue Energetics Research Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii, Honolulu, Hawaii 96822, United States
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6
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Singh SK, La Jeunesse J, Vuppuluri V, Son SF, Sun B, Chen Y, Chang AHH, Mebel AM, Kaiser RI. The Elusive Ketene (H
2
CCO) Channel in the Infrared Multiphoton Dissociation of Solid 1,3,5‐Trinitro‐1,3,5‐Triazinane (RDX). Chemphyschem 2020; 21:837-842. [DOI: 10.1002/cphc.201901202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/18/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Santosh K. Singh
- Department of Chemistry W. M. Keck Research Laboratory in AstrochemistryUniversity of Hawaii Honolulu HI 96822 HI USA
| | - Jesse La Jeunesse
- Department of Chemistry W. M. Keck Research Laboratory in AstrochemistryUniversity of Hawaii Honolulu HI 96822 HI USA
| | - Vasant Vuppuluri
- Mechanical Engineering Purdue Energetics Research CenterPurdue University West Lafayette IN 47907 USA
| | - Steven F. Son
- Mechanical Engineering Purdue Energetics Research CenterPurdue University West Lafayette IN 47907 USA
| | - Bing‐Jian Sun
- Department of ChemistryNational Dong Hwa University Shoufeng, Hualien 974 Taiwan
| | - Yue‐Lin Chen
- Department of ChemistryNational Dong Hwa University Shoufeng, Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of ChemistryNational Dong Hwa University Shoufeng, Hualien 974 Taiwan
| | - Alexander M. Mebel
- Department of Chemistry and BiochemistryFlorida International University Miami, Florida 33199 USA
| | - Ralf I. Kaiser
- Department of Chemistry W. M. Keck Research Laboratory in AstrochemistryUniversity of Hawaii Honolulu HI 96822 HI USA
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Nelson TR, White AJ, Bjorgaard JA, Sifain AE, Zhang Y, Nebgen B, Fernandez-Alberti S, Mozyrsky D, Roitberg AE, Tretiak S. Non-adiabatic Excited-State Molecular Dynamics: Theory and Applications for Modeling Photophysics in Extended Molecular Materials. Chem Rev 2020; 120:2215-2287. [PMID: 32040312 DOI: 10.1021/acs.chemrev.9b00447] [Citation(s) in RCA: 179] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Optically active molecular materials, such as organic conjugated polymers and biological systems, are characterized by strong coupling between electronic and vibrational degrees of freedom. Typically, simulations must go beyond the Born-Oppenheimer approximation to account for non-adiabatic coupling between excited states. Indeed, non-adiabatic dynamics is commonly associated with exciton dynamics and photophysics involving charge and energy transfer, as well as exciton dissociation and charge recombination. Understanding the photoinduced dynamics in such materials is vital to providing an accurate description of exciton formation, evolution, and decay. This interdisciplinary field has matured significantly over the past decades. Formulation of new theoretical frameworks, development of more efficient and accurate computational algorithms, and evolution of high-performance computer hardware has extended these simulations to very large molecular systems with hundreds of atoms, including numerous studies of organic semiconductors and biomolecules. In this Review, we will describe recent theoretical advances including treatment of electronic decoherence in surface-hopping methods, the role of solvent effects, trivial unavoided crossings, analysis of data based on transition densities, and efficient computational implementations of these numerical methods. We also emphasize newly developed semiclassical approaches, based on the Gaussian approximation, which retain phase and width information to account for significant decoherence and interference effects while maintaining the high efficiency of surface-hopping approaches. The above developments have been employed to successfully describe photophysics in a variety of molecular materials.
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Affiliation(s)
- Tammie R Nelson
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Alexander J White
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Josiah A Bjorgaard
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Andrew E Sifain
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States.,U.S. Army Research Laboratory , Aberdeen Proving Ground , Maryland 21005 , United States
| | - Yu Zhang
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Benjamin Nebgen
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | | | - Dmitry Mozyrsky
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Adrian E Roitberg
- Department of Chemistry , University of Florida , Gainesville , Florida 32611 , United States
| | - Sergei Tretiak
- Theoretical Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
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8
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Singh SK, Zhu C, Vuppuluri V, Son SF, Kaiser RI. Probing the Reaction Mechanisms Involved in the Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane by Energetic Electrons. J Phys Chem A 2019; 123:9479-9497. [PMID: 31589046 DOI: 10.1021/acs.jpca.9b08695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The decomposition mechanisms of 1,3,5-trinitro-1,3,5-triazinane (RDX) have been explored over the past decades, but as of now, a complete picture on these pathways has not yet emerged, as evident from the discrepancies in proposed reaction mechanisms and the critical lack of products and intermediates observed experimentally. This study exploited a surface science machine to investigate the decomposition of solid-phase RDX by energetic electrons at a temperature of 5 K. The products formed during irradiation were monitored online and in situ via infrared and UV-vis spectroscopy, and products subliming in the temperature programmed desorption phase were probed with a reflectron time-of-flight mass spectrometer coupled with soft photoionization at 10.49 eV (ReTOF-MS-PI). Infrared spectroscopy revealed the formation of water (H2O), carbon dioxide (CO2), dinitrogen oxide (N2O), nitrogen monoxide (NO), formaldehyde (H2CO), nitrous acid (HONO), and nitrogen dioxide (NO2). ReTOF-MS-PI identified 38 cyclic and acyclic products arranged into, for example, dinitro, mononitro, mononitroso, nitro-nitroso, and amines species. Among these molecules, 21 products such as N-methylnitrous amide (CH4N2O), 1,3,5-triazinane (C3H9N3), and N-(aminomethyl)methanediamine (C2H9N3) were detected for the first time in laboratory experiments; mechanisms based on the gas phase and condensed phase calculations were exploited to rationalize the formation of the observed products. The present studies reveal a rich, unprecedented chemistry in the condensed phase decomposition of RDX, which is significantly more complex than the unimolecular gas phase decomposition of RDX, thus leading us closer to an understanding of the decomposition chemistry of nitramine-based explosives.
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Affiliation(s)
| | | | - Vasant Vuppuluri
- Mechanical Engineering, Purdue Energetics Research Center , Purdue University , 500 Allison Road , West Lafayette , Indiana 47907-2088 , United States
| | - Steven F Son
- Mechanical Engineering, Purdue Energetics Research Center , Purdue University , 500 Allison Road , West Lafayette , Indiana 47907-2088 , United States
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9
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Wang H, Qi D, Yu X, Zhang Y, Zhang Z, Xu T, Zhang X, Dai S, Shen X, Song B, Zhang P, Xu Y. In-Situ and Ex-Situ Characterization of Femtosecond Laser-Induced Ablation on As₂S₃ Chalcogenide Glasses and Advanced Grating Structures Fabrication. MATERIALS (BASEL, SWITZERLAND) 2018; 12:E72. [PMID: 30587777 PMCID: PMC6337224 DOI: 10.3390/ma12010072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 11/16/2022]
Abstract
Femtosecond laser pulse of 800 nm wavelength and 150 fs temporal width ablation of As₂S₃ chalcogenide glasses is investigated by pump-probing technology. At lower laser fluence (8.26 mJ/cm²), the surface temperature dropping to the melting point is fast (about 43 ps), which results in a clean hole on the surface. As the laser fluence increases, it takes a longer time for lattice temperature to cool to the melting point at high fluence (about 200 ps for 18.58 mJ/cm², about 400 ps for 30.98 mJ/cm²). The longer time of the surface heating temperature induces the melting pool in the center, and accelerates material diffusing and gathering surrounding the crater, resulting in the peripheral rim structure and droplet-like structure around the rim. In addition, the fabricated long periodic As₂S₃ glasses diffraction gratings can preserve with high diffraction efficiency by laser direct writing technology.
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Affiliation(s)
- Hongyang Wang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Dongfeng Qi
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
- College of Mechanical and Electronic Engineering, Chaohu University, Hefei 230000, China.
| | - Xiaohan Yu
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Yawen Zhang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Zifeng Zhang
- College of Mechanical and Electronic Engineering, Chaohu University, Hefei 230000, China.
| | - Tiefeng Xu
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Xiaowei Zhang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Shixun Dai
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Xiang Shen
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Baoan Song
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Peiqing Zhang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
| | - Yinsheng Xu
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.
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11
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Ampadu Boateng D, Gutsev GL, Jena P, Tibbetts KM. Dissociation dynamics of 3- and 4-nitrotoluene radical cations: Coherently driven C–NO2bond homolysis. J Chem Phys 2018; 148:134305. [DOI: 10.1063/1.5024892] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Derrick Ampadu Boateng
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, USA
| | - Gennady L. Gutsev
- Department of Physics, Florida A&M University, Tallahassee, Florida 32307, USA
| | - Puru Jena
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, USA
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12
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Ge NN, Bai S, Chang J, Ji GF. Shock response of condensed-phase RDX: molecular dynamics simulations in conjunction with the MSST method. RSC Adv 2018; 8:17312-17320. [PMID: 35539229 PMCID: PMC9080422 DOI: 10.1039/c8ra00409a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 05/03/2018] [Indexed: 11/21/2022] Open
Abstract
We have performed molecular dynamics simulations in conjunction with the multiscale shock technique (MSST) to study the initial chemical processes of condensed-phase RDX under various shock velocities (8 km s−1, 10 km s−1 and 11 km s−1).
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Affiliation(s)
- Ni-Na Ge
- State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials
- Southwest University of Science and Technology
- Mianyang 621010
- P. R. China
| | - Sha Bai
- Laboratory for Shock Wave and Detonation Physics Research
- Institute of Fluid Physics
- Chinese Academy of Engineering Physics
- Mianyang
- P. R. China
| | - Jing Chang
- Institute of Solid State Physics
- Sichuan Normal University
- Chengdu 610101
- P. R. China
| | - Guang-Fu Ji
- Laboratory for Shock Wave and Detonation Physics Research
- Institute of Fluid Physics
- Chinese Academy of Engineering Physics
- Mianyang
- P. R. China
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13
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Nabiev SS, Palkina LA. Modern technologies for detection and identification of explosive agents and devices. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2017. [DOI: 10.1134/s1990793117050190] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Zeng Z, Bernstein ER. Photoelectron spectroscopy and density functional theory studies of N-rich energetic materials. J Chem Phys 2016; 145:164302. [DOI: 10.1063/1.4964944] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Zhen Zeng
- Department of Chemistry, NSF ERC for Extreme Ultraviolet Science and Technology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Elliot R. Bernstein
- Department of Chemistry, NSF ERC for Extreme Ultraviolet Science and Technology, Colorado State University, Fort Collins, Colorado 80523, USA
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15
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Akin FA. Ionisation energy, electron affinity, and mass spectral decomposition mechanisms of RDX isomers upon electron attachment and electron ionisation. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1246759] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- F. A. Akin
- Department of Chemistry, Boğaziçi University, Bebek, Istanbul/Turkey
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16
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Akin F. Mass spectral decomposition mechanisms of RDX isomers upon electron attachment and electron ionisation: a DFT study of normal mode activation incorporating Duschinsky rotations. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1229059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- F.A. Akin
- Department of Chemistry, Boğaziçi University, Istanbul, Turkey
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Myers TW, Bjorgaard JA, Brown KE, Chavez DE, Hanson SK, Scharff RJ, Tretiak S, Veauthier JM. Energetic Chromophores: Low-Energy Laser Initiation in Explosive Fe(II) Tetrazine Complexes. J Am Chem Soc 2016; 138:4685-92. [PMID: 26986744 DOI: 10.1021/jacs.6b02155] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The synthesis and characterization of air stable Fe(II) coordination complexes with tetrazine and triazolo-tetrazine ligands and perchlorate counteranions have been achieved. Time-dependent density functional theory (TD-DFT) was used to model the structural, electrochemical, and optical properties of these materials. These compounds are secondary explosives that can be initiated with Nd:YAG laser light at lower energy thresholds than those of PETN. Furthermore, these Fe(II) tetrazine complexes have significantly lower sensitivity than PETN toward mechanical stimuli such as impact and friction. The lower threshold for laser initiation was achieved by altering the electronic properties of the ligand scaffold to tune the metal ligand charge transfer (MLCT) bands of these materials from the visible into the near-infrared region of the electromagnetic spectrum. Unprecedented decrease in both the laser initiation threshold and the mechanical sensitivity makes these materials the first explosives that are both safer to handle and easier to initiate than PETN with NIR lasers.
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Affiliation(s)
- Thomas W Myers
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Josiah A Bjorgaard
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Kathryn E Brown
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - David E Chavez
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Susan K Hanson
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - R Jason Scharff
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Jacqueline M Veauthier
- M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States
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18
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Prediction of electronically nonadiabatic decomposition mechanisms of isolated gas phase nitrogen-rich energetic salt: Guanidium-triazolate. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Shin JW, Bernstein ER. Vacuum ultraviolet photoionization of carbohydrates and nucleotides. J Chem Phys 2015; 140:044330. [PMID: 25669546 DOI: 10.1063/1.4862829] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5(')-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.
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Affiliation(s)
- Joong-Won Shin
- Division of Science, Governors State University, University Park, Illinois 60484-0975, USA
| | - Elliot R Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA
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Myers TW, Chavez DE, Hanson SK, Scharff RJ, Scott BL, Veauthier JM, Wu R. Independent Control of Optical and Explosive Properties: Pyrazole–Tetrazine Complexes of First Row Transition Metals. Inorg Chem 2015; 54:8077-86. [DOI: 10.1021/acs.inorgchem.5b01313] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Thomas W. Myers
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - David E. Chavez
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Susan K. Hanson
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - R. Jason Scharff
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Brian L. Scott
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Jacqueline M. Veauthier
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
| | - Ruilian Wu
- M Division, ‡Chemistry Division, §Materials Physics and Applications, and ∥Bioscience Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, United States
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Appalakondaiah S, Vaitheeswaran G, Lebègue S. Dispersion Corrected Structural Properties and Quasiparticle Band Gaps of Several Organic Energetic Solids. J Phys Chem A 2015; 119:6574-81. [DOI: 10.1021/acs.jpca.5b04233] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Appalakondaiah
- Advanced
Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500 046, India
| | - G. Vaitheeswaran
- Advanced
Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500 046, India
| | - S. Lebègue
- Laboratoire
de Crystallographie, Résonance Magnétique et Modélisations
(CRM2, UMR CNRS 7036), Institut Jean Barriol, Université de Lorraine, BP 239, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France
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22
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Gares KL, Bykov SV, Brinzer T, Asher SA. Solution and Solid Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) Ultraviolet (UV) 229 nm Photochemistry. APPLIED SPECTROSCOPY 2015; 69:545-554. [PMID: 25812170 DOI: 10.1366/14-07622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We measured the 229 nm deep-ultraviolet resonance Raman (DUVRR) spectra of solution and solid-state hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). We also examined the photochemistry of RDX both in solution and solid states. RDX quickly photodegrades with a solution quantum yield of φ ~ 0.35 as measured by high-performance liquid chromatography (HPLC). New spectral features form over time during the photolysis of RDX, indicating photoproduct formation. The photoproduct(s) show stable DUVRR spectra at later irradiation times that allow standoff detection. In the solution-state photolysis, nitrate is a photoproduct that can be used as a signature for detection of RDX even after photolysis. We used high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS) and gas chromatography mass spectrometry (GCMS) to determine some of the major solution-state photoproducts. X-ray photoelectron spectroscopy (XPS) was also used to determine photoproducts formed during solid-state RDX photolysis.
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23
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Yuan B, Yu Z, Bernstein ER. Initial Mechanisms for the Decomposition of Electronically Excited Energetic Salts: TKX-50 and MAD-X1. J Phys Chem A 2015; 119:2965-81. [DOI: 10.1021/jp510995z] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Bing Yuan
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Zijun Yu
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Elliot R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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24
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Ju XH, Wang ZY, Qiu L. Theoretical Study of Heterocyclic Nitro Compounds for Use as Novel Explosives and Propellants. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200800189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Bayat Y, Mostafavi MMA. Silica Sulfuric Acid/HNO 3as a Novel Heterogeneous System for the Nitrolysis of DADN to HMX under Mild Conditions. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.11.3551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Bhattacharya A, Guo Y, Bernstein ER. A comparison of the decomposition of electronically excited nitro-containing molecules with energetic moieties C–NO2, N–NO2, and O–NO2. J Chem Phys 2012; 136:024321. [DOI: 10.1063/1.3668139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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Zhang C, Li Y, Xiong Y, Wang X, Zhou M. Acid and Alkali Effects on the Decomposition of HMX Molecule: A Computational Study. J Phys Chem A 2011; 115:11971-8. [DOI: 10.1021/jp204698b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chaoyang Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China
- Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), P.O. Box 919-327, Mianyang, Sichuan 621900, China
| | - Yuzhen Li
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Ying Xiong
- Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), P.O. Box 919-327, Mianyang, Sichuan 621900, China
| | - Xiaolin Wang
- China Academy of Engineering Physics (CAEP), P.O. Box 919-1, Mianyang, Sichuan 621900, China
| | - Mingfei Zhou
- Department of Chemistry, Fudan University, Shanghai 200433, China
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28
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He ZY, Luo J, Lu CX, Wang P, Xu R, Li JS. Preparation of HMX by Catalytic Nitrolysis of DPT in AIL-N2O5-HNO3System. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.8.2677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Bhattacharya A, Bernstein ER. Nonadiabatic Decomposition of Gas-Phase RDX through Conical Intersections: An ONIOM-CASSCF Study. J Phys Chem A 2011; 115:4135-47. [DOI: 10.1021/jp109152p] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- A. Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
| | - E. R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
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30
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Guo Y, Bhattacharya A, Bernstein ER. Ultrafast S1 to S0 Internal Conversion Dynamics for Dimethylnitramine through a Conical Intersection. J Phys Chem A 2011; 115:9349-53. [DOI: 10.1021/jp109150u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuanqing Guo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Atanu Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Elliot R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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31
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Bhattacharya A, Guo Y, Bernstein ER. Nonadiabatic reaction of energetic molecules. Acc Chem Res 2010; 43:1476-85. [PMID: 20931955 DOI: 10.1021/ar100067f] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Energetic materials store a large amount of chemical energy that can be readily converted into mechanical energy via decomposition. A number of different ignition processes such as sparks, shocks, heat, or arcs can initiate the excited electronic state decomposition of energetic materials. Experiments have demonstrated the essential role of excited electronic state decomposition in the energy conversion process. A full understanding of the mechanisms for the decomposition of energetic materials from excited electronic states will require the investigation and analysis of the specific topography of the excited electronic potential energy surfaces (PESs) of these molecules. The crossing of multidimensional electronic PESs creates a funnel-like topography, known as conical intersections (CIs). CIs are well established as a controlling factor in the excited electronic state decomposition of polyatomic molecules. This Account summarizes our current understanding of the nonadiabatic unimolecular chemistry of energetic materials through CIs and presents the essential role of CIs in the determination of decomposition pathways of these energetic systems. Because of the involvement of more than one PES, a decomposition process involving CIs is an electronically nonadiabatic mechanism. Based on our experimental observations and theoretical calculations, we find that a nonadiabatic reaction through CIs dominates the initial decomposition process of energetic materials from excited electronic states. Although the nonadiabatic behavior of some polyatomic molecules has been well studied, the role of nonadiabatic reactions in the excited electronic state decomposition of energetic molecules has not been well investigated. We use both nanosecond energy-resolved and femtosecond time-resolved spectroscopic techniques to determine the decomposition mechanism and dynamics of energetic species experimentally. Subsequently, we employ multiconfigurational methodologies (such as, CASSCF, CASMP2) to model nonadiabatic molecular processes of energetic molecules computationally. Synergism between experiment and theory establishes a coherent description of the nonadiabatic reactivity of energetic materials at a molecular level. Energetic systems discussed in this Account are nitramine- and furazan-based species. Both energetic species and their respective model systems, which are not energetic, are studied and discussed in detail. The model systems have similar molecular structures to those of the energetic species and help significantly in understanding the decomposition behavior of the larger and more complex energetic molecules. Our results for the above systems of interest confirm the existence of CIs and energy barriers on the PESs of interest. The presence of the CIs and barriers along the various reaction coordinates control the nonadiabatic behavior of the decomposition process. The detailed nature of the PESs and their CIs consequently differentiate the energetic systems from model systems. Energy barriers to the chemically relevant low-lying CIs of a molecule determine whether that molecule is more or less "energetic".
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Affiliation(s)
- Atanu Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado
| | - Yuanqing Guo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado
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32
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Roberson SD, Sausa RC. Laser-based detection of TNT and RDX residues in real time under ambient conditions. APPLIED SPECTROSCOPY 2010; 64:760-766. [PMID: 20615289 DOI: 10.1366/000370210791666327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We detect thin films of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-hexanitro-1,3,5-triazine (RDX) by one- and two-laser photofragmentation-fragment detection spectroscopy in real time at ambient temperature and pressure. In the one-laser technique, a laser tuned to 226 nm excites the energetic material and both generates the characteristic NO photofragments and facilitates their detection by resonance-enhanced multiphoton ionization (REMPI) using their A-X (0,0) transitions near 226 nm. In contrast, in the two-laser technique, a 454 nm laser generates the analyte molecule in the gas phase by matrix-assisted desorption, and a second laser tuned to 226 nm both photofragments it and ionizes the resulting NO. We report the effects of laser energy, analyte concentration, and matrix concentration on the ion signal and determine the rotational temperatures of the NO photofragments from Boltzmann, rotational distribution analysis of the REMPI spectra. We achieve limits of detection (S/N = 3) of hundreds of ng/cm(2) for both techniques under ambient conditions with a positive signal identification as low as 70 pg using a single 226 nm laser pulse of approximately 50 microJ.
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Affiliation(s)
- Stephen D Roberson
- US Army Research Laboratory, RDRL-WML-B, Aberdeen Proving Ground, Maryland 21005-5069, USA
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33
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Headrick JM, Reichardt TA, Settersten TB, Bambha RP, Kliner DAV. Application of laser photofragmentation-resonance enhanced multiphoton ionization to ion mobility spectrometry. APPLIED OPTICS 2010; 49:2204-2214. [PMID: 20390024 DOI: 10.1364/ao.49.002204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We demonstrate detection of nitro-containing compounds with laser photofragmentation (PF) coupled with resonance enhanced multiphoton ionization (REMPI) and ion mobility spectrometry (IMS). In PF-REMPI, a laser dissociates the parent molecules, producing fragments that can then be ionized by absorption of additional laser photons. The production of these ions strongly depends on the wavelength of laser light, with ion yields corresponding to the absorption spectrum of the fragments [nitric oxide (NO) in the present case]. Combining IMS with PF-REMPI provides further specificity, separating ions according to their mobilities through an atmospheric-pressure drift tube. In this work, we use a pulsed UV laser to examine the characteristics of atmospheric-pressure PF-REMPI, the chemistry occurring in the ionization region and drift tube, and the viability of detecting ions created by both resonance-enhanced and nonresonant ionization. Probing NO in a helium-nitrogen bath, we demonstrate that the detection of ions displays single-shot response to changes in ion generation, with an ion extraction-to-collection efficiency of approximately 12%. We then evaluate the sensitivity and specificity of PF-REMPI/IMS as applied to the detection of both the explosive surrogate 2, 4-dinitrotoluene and the nuisance compound nitrobenzene.
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Affiliation(s)
- Jeffrey M Headrick
- Sandia National Laboratories, P.O. Box 969, MS 9056, Livermore, California 94551, USA
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34
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Wang Q, Ng D, Mannan MS. Study on the Reaction Mechanism and Kinetics of the Thermal Decomposition of Nitroethane. Ind Eng Chem Res 2009. [DOI: 10.1021/ie900849n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Qingsheng Wang
- Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122
| | - Dedy Ng
- Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122
| | - M. Sam Mannan
- Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122
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35
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Zhi HZ, Luo J, Feng GA, Lv CX. An efficient method to synthesize HMX by nitrolysis of DPT with N2O5 and a novel ionic liquid. CHINESE CHEM LETT 2009. [DOI: 10.1016/j.cclet.2008.12.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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36
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Bhattacharya A, Guo YQ, Bernstein ER. Experimental and Theoretical Exploration of the Initial Steps in the Decomposition of a Model Nitramine Energetic Material: Dimethylnitramine. J Phys Chem A 2009; 113:811-23. [DOI: 10.1021/jp807247t] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado
| | - Y. Q. Guo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado
| | - E. R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado
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37
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Guo YQ, Bhattacharya A, Bernstein ER. Photodissociation Dynamics of Nitromethane at 226 and 271 nm at Both Nanosecond and Femtosecond Time Scales. J Phys Chem A 2008; 113:85-96. [DOI: 10.1021/jp806230p] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Y. Q. Guo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
| | - A. Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
| | - E. R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
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38
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Wynn CM, Palmacci S, Kunz RR, Clow K, Rothschild M. Detection of condensed-phase explosives via laser-induced vaporization, photodissociation, and resonant excitation. APPLIED OPTICS 2008; 47:5767-5776. [PMID: 19122718 DOI: 10.1364/ao.47.005767] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We investigate the remote detection of explosives via a technique that vaporizes and photodissociates the condensed-phase material and detects the resulting vibrationally excited NO fragments via laser-induced fluorescence. The technique utilizes a single 7 ns pulse of a tunable laser near 236.2 nm to perform these multiple processes. The resulting blue-shifted fluorescence (226 nm) is detected using a photomultiplier and narrowband filter that strongly block the scatter of the pump laser off the solid media while passing the shorter wavelength photons. Various nitro-bearing compounds, including 2,6-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were detected with a signal-to-noise of 25 dB. The effects of laser fluence, wavelength, and sample morphology were examined.
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Affiliation(s)
- C M Wynn
- Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, Massachusetts 02420, USA.
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Patterson JE, Dreger ZA, Miao M, Gupta YM. Shock wave induced decomposition of RDX: time-resolved spectroscopy. J Phys Chem A 2008; 112:7374-82. [PMID: 18642891 DOI: 10.1021/jp800827b] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Time-resolved optical spectroscopy was used to examine chemical decomposition of RDX crystals shocked along the [111] orientation to peak stresses between 7 and 20 GPa. Shock-induced emission, produced by decomposition intermediates, was observed over a broad spectral range from 350 to 850 nm. A threshold in the emission response of RDX was found at about 10 GPa peak stress. Below this threshold, the emission spectrum remained unchanged during shock compression. Above 10 GPa, the emission spectrum changed with a long wavelength component dominating the spectrum. The long wavelength emission is attributed to the formation of NO2 radicals. Above the 10 GPa threshold, the spectrally integrated intensity increased significantly, suggesting the acceleration of chemical decomposition. This acceleration is attributed to bimolecular reactions between unreacted RDX and free radicals. These results provide a significant experimental foundation for further development of a decomposition mechanism for shocked RDX (following paper in this issue).
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Affiliation(s)
- James E Patterson
- Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816, USA
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Guo YQ, Bhattacharya A, Bernstein ER. Excited electronic state decomposition of furazan based energetic materials: 3,3′-diamino-4,4′-azoxyfurazan and its model systems, diaminofurazan and furazan. J Chem Phys 2008; 128:034303. [DOI: 10.1063/1.2822283] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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41
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Guo YQ, Greenfield M, Bhattacharya A, Bernstein ER. On the excited electronic state dissociation of nitramine energetic materials and model systems. J Chem Phys 2007; 127:154301. [DOI: 10.1063/1.2787587] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Ramos C, Dagdigian PJ. Effect of photochemistry on molecular detection by cavity ringdown spectroscopy: case study of an explosive-related compound. APPLIED OPTICS 2007; 46:6526-32. [PMID: 17846646 DOI: 10.1364/ao.46.006526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Explosives and explosive-related compounds usually have dissociative excited electronic states. We consider the effect of excited-state dissociation upon an absorption event on the UV cavity ringdown spectroscopy (CRDS) detection of these molecules. A change in the photon decay lifetime with increasing laser energy is demonstrated with vapors of 2,6-dinitrotoluene in the open atmosphere. The magnitude of the effect is modeled with coupled equations describing the time-dependent light intensity and molecular concentration within the cavity. The light intensities required within this model to explain the observed changes in the photon decay lifetimes are consistent with the light intensities expected within the cavity under our experimental conditions. It was also found that the slow diffusion of the molecules in static air can magnify the effect of photochemistry on UV CRDS trace detection of molecules with dissociative excited states.
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Affiliation(s)
- Christopher Ramos
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
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