能量染色体:在爆炸性铁中低能激光启动
Thomas W Myers1, Josiah A Bjorgaard1, Kathryn E Brown1
1M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States.
Journal of the American Chemical Society
|March 18, 2016
概括
研究人员开发出新的铁协调复合物, 与PETN相比,这些由近红外激光激发的新材料具有较低的能量值和较低的冲击和摩擦灵敏度.
科学领域:
- 无机化学
- 材料科学
- 物理化学
背景情况:
- 二次爆炸物是重要的能量材料.
- 虽然PETN是一种基准二级爆炸物,但在处理和启动方面存在局限性.
- 开发更安全,更容易引爆的爆炸物是研究的主要目标.
研究的目的:
- 合成和表征新的稳定性铁 (II) 协调复合物.
- 调查这些复合物的潜力作为可调节的启动性质的二次爆炸物.
- 将它们的安全性和启动特性与PETN进行比较.
主要方法:
- 用四和三醇-四连体合成Fe (II) 复合物.
- 使用光谱和电化学技术进行表征.
- 时间依赖密度函数理论 (TD-DFT) 用于建模属性.
- 激光启动和机械敏感性测试
主要成果:
- 成功合成并表征了稳定在空气中的Fe (II) 复合物.
- 这些复合体的激光启动能量值低于PETN.
- 与PETN相比,对冲击和摩擦的敏感性显著降低.
- TD-DFT建模与可调节光学属性的相关电子结构修改 (MLCT频段).
结论:
- 开发的Fe (II) 四复合物代表了一类新的二次爆炸物.
- 它们具有前所未有的机械灵敏度和较低的激光启动值的组合.
- 将金属联体电荷传输带调整为近红外,使得操作更安全,NIR激光启动,超过PETN的性能.
相关概念视频
01:26Photochemical Electrocyclic Reactions: Stereochemistry
2.4K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
2.4K
01:25Deactivation Processes: Jablonski Diagram
2.2K
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
2.2K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.8K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.8K
03:02Colors and Magnetism
14.5K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
14.5K
01:20Atomic Emission Spectroscopy: Overview
4.2K
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
4.2K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
49.5K