Site-Specific Photodecomposition in Conjugated Energetic Materials

Lystrom, Levi; Zhang, Yu; Tretiak, Sergei; Nelson, Tammie

doi:10.1021/acs.jpca.8b04381

Title: Site-Specific Photodecomposition in Conjugated Energetic Materials

Abstract

Nonadiabatic excited-state molecular dynamics (NEXMD) has been used to study photodecomposition in a class of recently synthesized bicyclic conjugated energetic materials (CEMs) composed of fused tetrazole and tetrazine derivatives with increasing oxygen substitutions. Modification by oxygen functionalization has already been demonstrated to increase the two-photon absorption intensity in the target CEMs while simultaneously improving oxygen balance. Photodecomposition mechanisms in materials that undergo nonlinear absorption could be used to achieve controlled, direct optical initiation. For this study, we use NEXMD simulations to model the nonradiative relaxation and photodecomposition in CEMs following photoexcitation by a simulated Nd:YAG laser pulse. Excess electronic energy is quickly converted into vibrational energy on a sub-100 fs time scale resulting in bond dissociation. We find that, for the studied tetrazine derivatives, the bicyclic framework is an important structural feature that enhances the photochemical quantum yield and the high atomic oxygen content increases the relaxation lifetime and opens additional photodissociation pathways targeting the oxygen-substituted sites. The presented analysis scheme based on bond orders in the swarm of NEXMD trajectories is a useful tool for determining photochemical reactions.

Authors:

Lystrom, Levi ^[1];

^[2];

^[2]

Los Alamos National Lab. (LANL), Los Alamos, NM (United States); North Dakota State Univ., Fargo, ND (United States). Dept. of Chemistry and Biochemistry
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:: 2018-06-29

Research Org.:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1461403

Report Number(s):: LA-UR-18-24161
Journal ID: ISSN 1089-5639

Grant/Contract Number:: AC52-06NA25396

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Additional Journal Information:: Journal Volume: 122; Journal Issue: 29; Journal ID: ISSN 1089-5639

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE

Citation Formats


                    Lystrom, Levi, Zhang, Yu, Tretiak, Sergei, and Nelson, Tammie. Site-Specific Photodecomposition in Conjugated Energetic Materials.  United States: N. p., 2018. 
Web.  doi:10.1021/acs.jpca.8b04381.

Copy to clipboard


                    Lystrom, Levi, Zhang, Yu, Tretiak, Sergei, & Nelson, Tammie. Site-Specific Photodecomposition in Conjugated Energetic Materials.  United States.  https://doi.org/10.1021/acs.jpca.8b04381

Copy to clipboard


                    Lystrom, Levi, Zhang, Yu, Tretiak, Sergei, and Nelson, Tammie. Fri .  
"Site-Specific Photodecomposition in Conjugated Energetic Materials".  United States.  https://doi.org/10.1021/acs.jpca.8b04381.  https://www.osti.gov/servlets/purl/1461403.

Copy to clipboard


                    
@article{osti_1461403,

  title        = {Site-Specific Photodecomposition in Conjugated Energetic Materials},

  author       = {Lystrom, Levi and Zhang, Yu and Tretiak, Sergei and Nelson, Tammie},

  abstractNote = {Nonadiabatic excited-state molecular dynamics (NEXMD) has been used to study photodecomposition in a class of recently synthesized bicyclic conjugated energetic materials (CEMs) composed of fused tetrazole and tetrazine derivatives with increasing oxygen substitutions. Modification by oxygen functionalization has already been demonstrated to increase the two-photon absorption intensity in the target CEMs while simultaneously improving oxygen balance. Photodecomposition mechanisms in materials that undergo nonlinear absorption could be used to achieve controlled, direct optical initiation. For this study, we use NEXMD simulations to model the nonradiative relaxation and photodecomposition in CEMs following photoexcitation by a simulated Nd:YAG laser pulse. Excess electronic energy is quickly converted into vibrational energy on a sub-100 fs time scale resulting in bond dissociation. We find that, for the studied tetrazine derivatives, the bicyclic framework is an important structural feature that enhances the photochemical quantum yield and the high atomic oxygen content increases the relaxation lifetime and opens additional photodissociation pathways targeting the oxygen-substituted sites. The presented analysis scheme based on bond orders in the swarm of NEXMD trajectories is a useful tool for determining photochemical reactions.},

  doi          = {10.1021/acs.jpca.8b04381},

  journal      = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},

  number       = 29,

  volume       = 122,

  place        = {United States},

  year         = {2018},

  month        = {6}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1021/acs.jpca.8b04381

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 5 works

Citation information provided by
Web of Science

Figures / Tables:

Figure 1.: Chemical structures of N3-nitro-1,2,4,5-tetrazine-3,6diamine (ANATz), tetrazolo[1,5-b][1,2,4,5]tetrazine-6-amine (ATT), and tetrazolo[1,5-b][1,2,4,5]tetrazine-6-amine with one (ATTO) and two (ATTO₂) O substitutions. Bonds involved in the initial photodissociation step are labeled.

All figures and tables (6 total)

Save / Share:

Export Metadata

Save to My Library

Figures / Tables found in this record:

Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.

Similar Records in DOE PAGES and OSTI.GOV collections:

Photoactive High Explosives: Substituents Effects on Tetrazine Photochemistry and Photophysics

Journal Article McGrane, Shawn David ; Bolme, Cynthia Anne ; Greenfield, Margo Torello ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

High explosives that are photoactive, i.e., can be initiated with light, offer significant advantages in reduced potential for accidental electrical initiation. In this study, we examined a series of structurally related tetrazine based photoactive high explosive materials to detail their photochemical and photophysical properties. Using photobleaching infrared absorption, we determined quantum yields of photochemistry for nanosecond pulsed excitation at 355 and 532 nm. Changes in mass spectrometry during laser irradiation in vacuum measured the evolution of gaseous products. Fluorescence spectra, quantum yields, and lifetimes were measured to observe radiative channels of energy decay that compete with photochemistry. For the 6more »« less
Cited by 12
https://doi.org/10.1021/acs.jpca.5b11851

Full Text Available
Ultrafast X-ray Transient Absorption Spectroscopy of Gas-Phase Photochemical Reactions: A New Universal Probe of Photoinduced Molecular Dynamics

Journal Article Bhattacherjee, Aditi ; Leone, Stephen R. - Accounts of Chemical Research

Time-resolved spectroscopic investigations of light-induced chemical reactions with universal detection capitalize recently on single-photon molecular probing using laser pulses in the extreme ultraviolet or X-ray regimes. Direct and simultaneous mappings of the time-evolving populations of ground-state reactants, Franck-Condon (FC) and transition state regions, excited-state intermediates and conical intersections (CI), and photoproducts in photochemical reactions utilize probe pulses that are broadband and energy-tunable. The limits on temporal resolution are set by the transit- or dwell-time of the photoexcited molecules at specific locations on the potential energy surface, typically ranging from a few femtoseconds to several hundred picoseconds. Femtosecond high-harmonic generation (HHG)more »« less
Cited by 34
https://doi.org/10.1021/acs.accounts.8b00462

Full Text Available
Ultrafast Photodissociation Dynamics of Nitromethane

Journal Article Nelson, Tammie Renee ; Bjorgaard, Josiah August ; Greenfield, Margo Torello ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Nitromethane (NM), a high explosive (HE) with low sensitivity, is known to undergo photolysis upon ultraviolet (UV) irradiation. The optical transparency, homogeneity, and extensive study of NM make it an ideal system for studying photodissociation mechanisms in conventional HE materials. The photochemical processes involved in the decomposition of NM could be applied to the future design of controllable photoactive HE materials. In this work, the photodecomposition of NM from the nπ* state excited at 266 nm is being investigated on the femtosecond time scale. UV femtosecond transient absorption (TA) spectroscopy and excited state femtosecond stimulated Raman spectroscopy (FSRS) are combinedmore »« less
Cited by 33
https://doi.org/10.1021/acs.jpca.5b09776

Full Text Available
Two-photon absorption in conjugated energetic molecule

Journal Article Bjorgaard, Josiah August ; Sifain, Andrew ; Nelson, Tammie Renee ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Time-dependent density functional theory (TD-DFT) is used to investigate the relationship between molecular structure and one- and two-photon absorption (OPA and TPA, respectively) properties in novel and recently synthesized conjugated energetic molecules (CEMs). The molecular structure of CEMs can be strategically altered to influence the heat of formation and oxygen balance, two factors that can contribute to the sensitivity and strength of an explosive material. OPA and TPA are sensitive to changes in molecular structure as well, influencing optical range of excitation. We find calculated vertical excitation energies in good agreement with experiment for most molecules. Peak TPA intensities aremore »« less
Cited by 15
https://doi.org/10.1021/acs.jpca.6b03136

Full Text Available
Nonadiabatic Excited-State Molecular Dynamics for Open-Shell Systems

Journal Article Zhang, Yu ; Li, Linqiu ; Tretiak, Sergei ; ... - Journal of Chemical Theory and Computation

Nonadiabatic Molecular Dynamics (NAMD) of excited states has been widely used in the simulation of photoinduced phenomena. However, the inability to treat bond breaking and forming processes with single-reference electronic structure methods limits their application in photochemistry for extended molecular systems. In this work, the extension of excited-state NAMD for open-shell systems is developed and implemented in the NEXMD software. We present the spin-unrestricted CIS and TDSCF formalism for the ground and excited states, analytical derivatives, and nonadiabatic derivative couplings for the respective potential energy surfaces. Next, this methodology is employed to study the photochemical reaction of three model molecules.more »« less
Cited by 5
https://doi.org/10.1021/acs.jctc.9b00928

Full Text Available

Similar Records