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Updated: Jun 22, 2026

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
07:24

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

Published on: May 10, 2021

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通过MeV离子微波束分析评估金属有机框架中的组成梯度的非破坏性量化

Gyula Nagy1, Wanja Gschwind2, Sascha Ott2

  • 1Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden.

Analytical chemistry
|September 10, 2024
PubMed
概括

本研究介绍了一种使用离子束微分析的方法,用于测量金属有机框架 (MOF) 中的扩散系数. 我们量化了基于Zr的UiO-67-bpy MOF中的NiCl2扩散,得到1.72 × 10^-16 m^2s^-1.1的扩散系数.

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Mass Spectrometry: Molecular Fragmentation Overview01:20

Mass Spectrometry: Molecular Fragmentation Overview

The ionization of a molecule into a molecular ion inside the mass spectrometer causes instability in the molecule's structure due to the loss of an electron. This eventually leads to the fragmentation or breaking of some bonds in the molecule. The fragmentation occurs predominantly at specific bonds to yield relatively stable fragments.
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Mass Spectrometry: Long-Chain Alkane Fragmentation

The molecular ions of linear alkanes prefer to fragment at the carbon-carbon bond away from the end of the chain since the cleavage of an inner bond creates a stable carbocation and a stable radical. Consequently, the mass signals of linear alkanes feature intense peaks in the middle of the mass-to-charge ratio plot with weaker peaks on either end. The fragmentation of each carbon-carbon bond with the release of a methyl group in each splitting leads to prominent peaks in the mass spectra...
Mass Spectrometry: Alkene Fragmentation00:59

Mass Spectrometry: Alkene Fragmentation

Alkenes lose one electron from the unsaturated π bond upon ionization and form stable molecular ions. Further fragmentation of alkenes occurs through three different reaction pathways. The most prominent fragmentation is the cleavage at the allylic position. The resultant allylic carbocation is resonance stabilized. In the mass spectra of terminal alkenes, this fragment appears at a mass-to-charge ratio of 41. In the internal alkenes, where there are two choices of allylic cleavage, the...
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Mass Spectrometry: Carboxylic Acid, Ester, and Amide Fragmentation

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For example, the fragmentation of...
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