From Ignition to Photoelectron Spectroscopy Conical Intersection Impact the Study of Energetic Materials

2012 ◽  
Author(s):  
David R. Yarkony
Keyword(s):  
Photoelectron Spectroscopy ◽  
Energetic Materials ◽  
Conical Intersection

Surface Chemical Characterization Methods Applied to Energetic Materials

1992 ◽  
Vol 296 ◽  
Author(s):  
B. C. Beard ◽  
I. Sharma
Keyword(s):  
Photoelectron Spectroscopy ◽  
Energetic Materials ◽  
Chemical Characterization ◽  
Surface Chemical ◽  
Specific Chemical ◽  
Surface Mass ◽  
Characterization Methods ◽  
Gaseous Products ◽  
Increased Sensitivity ◽  
And Performance

AbstractThe reaction chemistry of energetic materials is often considered only with respect to the types and quantities of gaseous products formed. For a thorough understanding of the initi reaction steps, that largely determine the sensitivity of the material, both gaseous and solid products must be determined. In addition, it is the solid state partial decomposition intermediates remaining in a damaged material that can lead to increased sensitivity. The preference for the initial reactions to take place at the surface of particles and the low concentrations of intermediates formed demands the use of highly sensitive surface specific chemical probe techniques. State of the art surface chemical techniques will be discussed, focusing on x-ray photoelectron spectroscopy and surface mass spectrometry. Principles of operation and performance will be highlighted, comparisons will be made to bulk chemical analysis, and examples of applications will be presented.

scholarly journals Monitoring the effect of a control pulse on a conical intersection by time-resolved photoelectron spectroscopy

2011 ◽  
Vol 13 (19) ◽  
pp. 8681 ◽  
Author(s):  
Yasuki Arasaki ◽  
Kwanghsi Wang ◽  
Vincent McKoy ◽  
Kazuo Takatsuka
Keyword(s):  
Photoelectron Spectroscopy ◽  
Control Pulse ◽  
Conical Intersection ◽  
Time Resolved

scholarly journals Time-resolved photoelectron spectroscopy of wavepackets through a conical intersection in NO2

2010 ◽  
Vol 132 (12) ◽  
pp. 124307 ◽  
Author(s):  
Yasuki Arasaki ◽  
Kazuo Takatsuka ◽  
Kwanghsi Wang ◽  
Vincent McKoy
Keyword(s):  
Photoelectron Spectroscopy ◽  
Conical Intersection ◽  
Time Resolved

scholarly journals High-density HNIW/TNT cocrystal synthesized using a green chemical method

2018 ◽  
Vol 74 (4) ◽  
pp. 385-393 ◽  
Author(s):  
Yan Liu ◽  
Chongwei An ◽  
Jin Luo ◽  
Jingyu Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Energetic Materials ◽  
Chemical Method ◽  
Driving Forces ◽  
High Density ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Challenge ◽  
Hydrogen Bonded

The main challenge for achieving better energetic materials is to increase their density. In this paper, cocrystals of HNIW (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, often referred to as CL-20) with TNT (2,4,6-trinitrotoluene) were synthesized using ethanol in a green chemical method. The cocrystal was formulated as C13H11N15O18 and possesses a higher density (1.934 g cm−3) than published previously (1.846 g cm−3). This high-density cocrystal possesses a new structure, which can be substantiated by the different types of hydrogen bonds. The predominant driving forces that connect HNIW with TNT in the new cocrystal were studied at ambient conditions using single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform–infrared spectroscopy and Raman spectroscopy. The results reveal that the structure of the new HNIW/TNT cocrystals consists of three one-dimensional hydrogen-bonded chains exploiting the familiar HNIW–TNT multi-component supramolecular structure, in which two hydrogen-bonded chains are between —NO2 (HNIW) and —CH (TNT), and one hydrogen-bonded chain is between —CH (HNIW) and —NO2 (TNT). The changes to the electron binding energy and type of element in the new cocrystal were traced using X-ray photoelectron spectroscopy. Meanwhile, the physicochemical characteristics alter after cocrystallization due to the hydrogen bonding. It was found that the new HNIW/TNT cocrystal is more thermodynamically stable than HNIW. Thermodynamic aspects of new cocrystal decomposition are investigated in order to explain this observation. The detonation velocity of new HNIW/TNT cocrystals is 8631 m s−1, close to that of HNIW, whereas the mechanical sensitivity is lower than HNIW.

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

Spatially Resolved Photoelectron Spectroscopy: Recent Progress and Future Plans

1990 ◽  
Vol 48 (2) ◽  
pp. 388-389
Author(s):  
A. M. Bradshaw
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Reactivity ◽  
Target Material ◽  
Orbital Energy ◽  
Light Sources ◽  
Analytical Technique ◽  
Hartree Fock ◽  
Spatially Resolved ◽  
Koopmans Theorem ◽  
Surface Analytical Technique

X-ray photoelectron spectroscopy (XPS or ESCA) was not developed by Siegbahn and co-workers as a surface analytical technique, but rather as a general probe of electronic structure and chemical reactivity. The method is based on the phenomenon of photoionisation: The absorption of monochromatic radiation in the target material (free atoms, molecules, solids or liquids) causes electrons to be injected into the vacuum continuum. Pseudo-monochromatic laboratory light sources (e.g. AlKα) have mostly been used hitherto for this excitation; in recent years synchrotron radiation has become increasingly important. A kinetic energy analysis of the so-called photoelectrons gives rise to a spectrum which consists of a series of lines corresponding to each discrete core and valence level of the system. The measured binding energy, EB, given by EB = hv−EK, where EK is the kineticenergy relative to the vacuum level, may be equated with the orbital energy derived from a Hartree-Fock SCF calculation of the system under consideration (Koopmans theorem).

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