Related Experiment Video
Updated: May 5, 2026
06:53
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
7.5K
Energy deposition during electron-induced dissociation
J R Gord1, S R Horning, J M Wood
1Department of Chemistry, Purdue University, 47907, West Lafayette, IN, USA.
Journal of the American Society for Mass Spectrometry
|November 16, 2013
Summary
Electron-ion collisions activate mass-selected ions, allowing controlled energy deposition for fragmentation studies. This method offers tunable ion excitation, similar to electron-impact ionization.
Area of Science:
- Physical Chemistry
- Mass Spectrometry
- Chemical Physics
Background:
- Ion activation is crucial for studying molecular structure and dynamics.
- Electron-induced dissociation (EID) is a developing technique for ion activation.
- Understanding energy deposition in EID is key to controlling fragmentation.
Purpose of the Study:
- To investigate the internal energy deposition during electron-ion collisions for ion activation.
- To explore the mechanism of electron-induced dissociation in Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).
- To demonstrate control over ion excitation energy in EID.
Main Methods:
- Mass-selected ions (limonene and W(CO)n/+) were subjected to activation via electron-ion collisions in an FT-ICR MS.
- Fragmentation patterns were analyzed to infer internal energy deposition.
- Electron energy, flux, and interaction time were systematically varied.
Main Results:
- Characteristic fragmentations indicated that EID proceeds via multiple electron-ion collisions.
- The average internal energy deposited could be controlled and matched that of electron-impact ionization.
- Tunable ion excitation was achieved by manipulating electron parameters.
Conclusions:
- Electron-ion collision-induced dissociation is a controllable method for ion activation.
- This technique allows for selection of internal energy deposition, mimicking electron-impact ionization.
- EID offers a promising, tunable approach for mass spectrometry-based chemical analysis and research.
Related Concept Videos
01:20Mass Spectrometry: Molecular Fragmentation Overview
5.2K
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.
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
5.2K
01:21Chemical Ionization (CI) Mass Spectrometry
1.5K
The molecular ion peak of a molecule in the mass spectrum provides vital information for molecular identification. However, conventional electron impact ionization can lead to the rapid dissociation of some molecular ions before they reach the detector. A milder ionization method is required to increase the lifetime of such ionized analyte molecules. Chemical ionization (CI) is a gas-phase protonation reaction useful for mass-analyzing analyte molecules that are easily protonated to yield the...
1.5K
02:13Bond Dissociation Energy and Activation Energy
8.6K
Bond energy is the energy required to break a bond homolytically. These values are usually expressed in units of kcal/mol or kJ/mol and are referred to as bond dissociation energies when given for specific bonds or average bond energies when indicated for a given type of bond over many compounds. Firstly, the bond dissociation energy for a single bond is weaker than that of a double bond, which in turn is weaker than that of a triple bond. Secondly, hydrogen forms relatively strong bonds with...
8.6K
03:12Ionization Energy
32.7K
The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy (IE1). The first ionization energy for an element, X, is the energy required to form a cation with 1+ charge:
32.7K
00:59Mass Spectrometry: Alkene Fragmentation
3.8K
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...
3.8K
01:25Deactivation Processes: Jablonski Diagram
2.3K
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...
2.3K